[{"id":"to-the-spaceship","title":"From the first fire to interstellar space","emoji":"🚀","blurb":"A million years of one idea: a fire you control, pushed a little further each time, until a machine built from that same trick crosses into interstellar space.","minAge":16,"kidsCut":true,"lens":"science","group":"sky-space-and-time","beats":[{"event":"wonderwerk-earliest-controlled-fire","year":-1000000,"label":"Wonderwerk Cave — the oldest known controlled fire","emoji":"🔥","link":"Everything downstream starts here. Human ancestors were now keeping fire going on purpose, probably fire taken from wildfires rather than lit by hand — and every rocket engine ever built is, at heart, a fire kept burning on purpose.","kidsLink":"This is where our story begins. Long ago, our human ancestors learned to keep a fire going. Every rocket ever built, all the way to space, is really a fire kept burning on purpose.","minAge":4},{"event":"gunpowder-origins-850","year":850,"label":"Chinese alchemists find gunpowder","emoji":"🧨","link":"Searching for an elixir of immortality, Tang alchemists mixed saltpeter, sulfur and charcoal into a powder that carries its own oxidizer: the saltpeter releases oxygen as it burns. Nobody knew it yet, but a fire that brings its own oxygen is the seed of every rocket in this story.","kidsLink":"People had used fire for a million years. Then Chinese alchemists mixed three powders while trying to make a magic drink. By accident, they made a powder that carries its own oxygen, so it burns very fast.","minAge":7},{"event":"wujing-zongyao-gunpowder-formulas-1044","year":1044,"label":"The earliest known written gunpowder recipes","emoji":"💥","link":"A discovery locked inside one workshop dies there. Written into an army manual — recipes, bombs, fire-arrows — the formula could be copied, carried along trade and war routes, and improved by people who never met the alchemists who found it.","minAge":10},{"event":"flying-fire-lances-siege-of-kaifeng-1232","year":1232,"label":"Gunpowder at the siege of Kaifeng","emoji":"🎇","link":"Gunpowder weapons kept evolving. When the Mongols besieged Kaifeng in 1232, the Jin defenders fought back with bombs and fire lances that shot flame about three metres, and reports also describe fire arrows that may have been early rockets — though historians dispute when rockets truly began.","minAge":10},{"event":"al-rammah-book-of-military-devices-1280","year":1280,"label":"Al-Rammah writes down rocket recipes","emoji":"📜","link":"Rocketry probably spread west with the Mongols who besieged Kaifeng, who employed Chinese rocketry experts as mercenaries. Within decades the Syrian engineer Hasan al-Rammah wrote down 22 rocket recipes whose terminology still points back to a Chinese origin.","minAge":10},{"event":"hwacha-deployed-1451","year":1451,"label":"Korea fields the hwacha rocket cart","emoji":"🧨","link":"Gunpowder rocketry spread east as well as west. In Korea, a rocket cart first built in 1409 was improved on King Munjong's orders in 1451 into a hwacha that could launch a hundred rocket-arrows in one volley.","minAge":10},{"event":"kepler-first-two-laws-1609","year":1609,"label":"Kepler's laws of planetary motion","emoji":"🪐","link":"Now a second thread joins the story, because knowing how to push is useless if you do not know where things go. Kepler showed a planet's path is a precise curve you can calculate, which turned 'where will it be' from a mystery into arithmetic.","kidsLink":"Later, gunpowder was used to power rocket arrows. But nobody could say exactly where a flying thing would go. Johannes Kepler found the answer for planets: they travel in oval paths, not circles, and you can work out where they will be.","minAge":4},{"event":"newton-s-universal-gravitation","year":1687,"label":"Newton's Universal Gravitation","emoji":"🍎","link":"Kepler described the curves; Newton explained why they happen. His Principia set out laws of motion — when one body pushes on another, it is pushed back equally hard the opposite way — and showed the force pulling an apple down holds the Moon in orbit: the rules for how hard you must push to reach orbit.","kidsLink":"Kepler showed the paths planets follow. Isaac Newton explained why: the same force that pulls an apple down to the ground also keeps the Moon circling the Earth. Together their ideas are the recipe for how hard you must push something to make it orbit.","minAge":4},{"event":"tipu-sultan-fields-iron-war-rockets","year":1792,"label":"Tipu Sultan Fields Iron War Rockets","emoji":"🚀","link":"Back on the gunpowder thread: Mysore's armies cased their rockets in iron instead of paper, so the charge could burn at much higher pressure without bursting, giving more thrust and a far longer range. Rockets captured after Tipu's defeat in 1799 went to Britain, and within a decade British arsenals were copying them.","minAge":10},{"event":"congreve-turns-mysore-rockets-into-artillery-1804","year":1804,"label":"Congreve rebuilds Mysore's rocket at Woolwich","emoji":"🧨","link":"Several Mysorean rockets captured after Tipu Sultan's defeat were sent to Britain for study. From 1804 William Congreve experimented at Woolwich: the best rockets he could buy in London flew only 600 yards, but by 1806 his 32-pounders reached 3,000 and were later made in quantity: Mysore's idea, mass-produced.","minAge":10},{"event":"tsiolkovsky-rocket-equation-1903","year":1903,"label":"Tsiolkovsky's rocket equation","emoji":"🚀","link":"So far rockets had been weapons. In provincial Russia, a deaf schoolteacher published the mathematics of spaceflight: an equation linking how fast a rocket can go to how fast its exhaust leaves and how much of the rocket is fuel.","kidsLink":"For hundreds of years, rockets were used as weapons. Then in Russia, a schoolteacher who could not hear worked out the math for how rockets could fly into space.","minAge":4},{"event":"oberth-die-rakete-zu-den-planetenraeumen-1923","year":1923,"label":"The book that taught Germany to build rockets","emoji":"📘","link":"Foreign scientists took no notice of Tsiolkovsky. Two decades later in Germany, Hermann Oberth's rocket thesis was rejected as 'utopian'; he had it published privately, and its mathematics of escaping Earth's gravity fired up a whole generation of German rocket enthusiasts.","kidsLink":"Scientists in other countries took no notice of Tsiolkovsky's math. Twenty years later, in Germany, Hermann Oberth printed his own book about rockets. It showed how to escape Earth's gravity, and it got many rocket builders excited.","minAge":4},{"event":"goddard-launches-first-liquid-fueled-rocket","year":1926,"label":"Goddard Launches First Liquid-Fueled Rocket","emoji":"🚀","link":"Goddard's rocket burned liquid fuel, gasoline and liquid oxygen, instead of powder. Most liquid engines can be throttled, and some can be shut down and restarted: a fire you can control. His first flight rose just 12.5 metres, but it showed liquid fuels could power far larger rockets.","kidsLink":"Oberth's book got people in Germany excited about rockets. At about the same time, in the United States, Robert Goddard was building a real one. It burned liquid fuel instead of gunpowder. Engines like that can be turned up and down, and some can be switched off and on.","minAge":4},{"event":"mittelbau-dora-established","year":1943,"label":"Prisoners Begin Digging Mittelbau-Dora","emoji":"🚇","link":"The next leap was not made by curiosity. Nazi Germany scaled the liquid-fuel rocket up into a weapon, the V-2, and had it assembled inside a mountain by concentration-camp prisoners — more of whom died there than the rockets they built ever killed.","minAge":16},{"event":"v-2-rocket-becomes-first-object-to-reach-space","year":1944,"label":"V-2 Rocket Becomes First Object To Reach Space","emoji":"🚀","link":"Fired straight up on a test instead of at a city, that same weapon became the first human-made object to cross into space. After the war the Allies raced for its technology: Operation Paperclip took German engineers and captured V-2 parts to the United States, and the V-2 shaped later missiles and spaceflight.","kidsLink":"Liquid-fuel rockets grew much bigger and stronger. In 1944, a rocket called the V-2 shot straight up during a test. It flew higher than anything ever had before. It was the first human-made object to reach space.","minAge":4},{"event":"sputnik-1-first-satellite","year":1957,"label":"Sputnik 1: first satellite","emoji":"🛰️","link":"The V-2 went straight up; Sputnik 1 went around, the first artificial satellite to orbit Earth. Its success showed the USSR could potentially deliver nuclear weapons across continents, and it ignited the Space Race, as both superpowers sought to prove their superiority in spaceflight.","kidsLink":"The V-2 went straight up into space. Sputnik went further. It became the first satellite ever to circle the Earth.","minAge":4},{"event":"luna-1-luna-3-1959","year":1959,"label":"Luna 1 escapes Earth; Luna 3 bends its path","emoji":"🌙","link":"Sputnik proved a rocket could reach orbital speed; Luna 1 pushed further, becoming the first craft to escape Earth's gravity entirely. That October, Luna 3 added a new trick: letting the Moon's gravity bend its path home, the gravity assist that would later fling Voyager across the Solar System.","kidsLink":"Sputnik showed a rocket could circle the Earth. Luna 1 went further and flew all the way free of Earth's gravity. Then Luna 3 used the Moon's own pull to bend its path home, the same trick that would later send spacecraft flying past many planets.","minAge":4},{"event":"yuri-gagarin-first-human-in-space","year":1961,"label":"Yuri Gagarin: First Human In Space","emoji":"👨‍🚀","link":"Once you can put a payload into orbit and bring it back down through re-entry, the payload can be a person. One lap of the planet turned space from somewhere we send machines into somewhere we go.","kidsLink":"Sputnik proved a machine could circle the Earth. Once you can send something up and safely bring it back down, that something can be a person: Yuri Gagarin became the first human ever to fly into space.","minAge":4},{"event":"flandro-grand-tour-1964","year":1964,"label":"Flandro spots the Grand Tour alignment","emoji":"🧮","link":"Gagarin proved humans could ride a rocket into space, but the outer planets still needed machines. In 1964 JPL student Gary Flandro found a rare alignment of Jupiter, Saturn, Uranus and Neptune, occurring once every 175 years, letting one probe swing planet to planet on gravity, as Luna 3 had shown five years before.","kidsLink":"Gagarin showed a person could fly in space. But to visit the far-off planets, scientists needed a plan for robots. In 1964, a young scientist named Gary Flandro found that those planets would soon line up in a rare way. Then one spacecraft could visit several, swinging from each planet to the next using its gravity.","minAge":4},{"event":"moon-landing","year":1969,"label":"Moon landing","emoji":"🌕","link":"Orbit is a place you can leave from. Eight years after Gagarin, in a Space Race rooted in Cold War rivalry, a Saturn V rocket launched three astronauts to the Moon, and two of them, Neil Armstrong and Buzz Aldrin, landed on it.","kidsLink":"Gagarin proved a person could go to space and come home safely. Eight years later, a rocket called the Saturn V launched three astronauts to the Moon, and two of them landed on it.","minAge":4},{"event":"pioneer-10-jupiter-plaque","year":1972,"label":"Pioneer 10 heads to Jupiter","emoji":"🪐","link":"Apollo showed what rockets could do carrying people; three years later NASA sent a probe outward instead. Pioneer 10 was the first spacecraft to survive the asteroid belt and fly past Jupiter, whose gravity gave it the speed to escape the Solar System: proof the outer planets were reachable before Voyager.","kidsLink":"People had just landed on the Moon. Next, NASA sent a robot spacecraft named Pioneer 10 out toward the outer planets instead. It became the first spacecraft to safely cross the asteroid belt and fly past Jupiter, moving fast enough to one day leave the Solar System completely.","minAge":4},{"event":"voyager-probes-launched","year":1977,"label":"Voyager Probes Launched","emoji":"🛸","link":"Pioneer 10 had shown a probe could survive the long trip to Jupiter; the Voyagers were sent much farther. Launched on Titan-Centaur rockets and timed to the rare alignment Flandro had found, they could fly past Jupiter, Saturn and onward using each planet's own gravity for a boost.","kidsLink":"After Pioneer 10, NASA sent two more robots even farther. The planets had lined up just as Gary Flandro said they would. So the two Voyager spacecraft could fly past Jupiter and Saturn and keep going.","minAge":4},{"event":"voyager-1-jupiter-saturn-flybys-1980","year":1980,"label":"Voyager 1 flies past Jupiter, then Saturn","emoji":"🪐","link":"The planned trajectory paid off: Jupiter's gravity bent and sped Voyager 1 toward Saturn, and its close pass of Saturn and the moon Titan swung it below Saturn's south pole and out of the plane the planets orbit in — onward toward interstellar space with no bigger rocket needed.","kidsLink":"Voyager 1's path was planned so each planet would give it a free push. Jupiter's gravity sped it toward Saturn. Then Saturn's gravity flung it out toward the space between the stars.","minAge":4},{"event":"voyager-1-interstellar-space","year":2012,"label":"Voyager 1 reaches interstellar space","emoji":"🌠","link":"The last step needed no bigger fire, just cleverness: a 1970s rocket plus speed stolen from Jupiter and Saturn as it flew past them. Voyager 1 crossed out of the Sun's bubble of wind and into interstellar space — a descendant of a campfire, still calling home from between the stars.","kidsLink":"All that speed from Jupiter and Saturn's gravity finally paid off. In 2012, Voyager 1 flew out of the Sun's bubble of wind. It became the first human-made object to reach the space between the stars.","minAge":4}]},{"id":"to-the-nuclear-plant","title":"From the atom to the power station","emoji":"☢️","blurb":"A single line of curiosity runs from ancient Greek and Indian guesses that matter has smallest parts, through a fogged photographic plate, to the bombs that destroyed two cities, the reactors that light our homes, and the accidents and hopes that still divide us about them.","minAge":13,"kidsCut":true,"lens":"science","group":"power-and-inventions","beats":[{"event":"kanada-proposes-indivisible-atoms","year":-600,"label":"Kanada Proposes Indivisible Atoms","emoji":"⚛️","link":"This whole story starts with a question, not an experiment: what is everything actually made of? Sometime between the 6th and 2nd centuries BCE in India, Kanada proposed that matter breaks down into tiny indivisible paramanu — a guess this journey spends the next two thousand years testing.","kidsLink":"This story starts with a big question: what is everything made of? Long ago in India, a thinker named Kanada guessed that everything is built from tiny bits too small to break. People have been testing that guess ever since.","minAge":4},{"event":"democritus-and-atoms","year":-430,"label":"Democritus Imagines the Atom","emoji":"⚛️","link":"In Greece, probably independently, Democritus reached the same pure guess: everything is made of tiny, invisible, unbreakable pieces, atoms, moving in empty space. It was a guess, not an experiment, and everything that follows is more than two thousand years of people finding out whether it was right.","kidsLink":"Far away in Greece, a thinker named Democritus had a very similar idea. He said everything is made of tiny pieces too small to see, and he called them atoms.","minAge":4},{"event":"dalton-proposes-modern-atomic-theory","year":1803,"label":"Dalton Proposes Modern Atomic Theory","emoji":"⚛️","link":"The guess finally became chemistry. Dalton proposed that each element is made of identical atoms with a characteristic weight, and that compounds form when atoms combine in fixed whole-number ratios, and the atom moved out of philosophy and into the laboratory.","kidsLink":"Democritus could only guess about atoms. Two thousand years later, a chemist named John Dalton said each element is made of its own matching atoms. He said atoms join up in neat, whole-number amounts.","minAge":4},{"event":"xrays-1895","year":1895,"label":"Röntgen discovers X-rays","emoji":"🩻","link":"For most of a century the atom was pictured as indivisible. Then in 1895 in Würzburg, Germany, Röntgen noticed a mysterious ray from a cathode-ray tube making a screen glow up to two metres away, and imaged the bones of his wife's hand. No one knew what these X-rays were, and the hunt soon led inside the atom.","kidsLink":"Dalton pictured atoms as tiny bits that could not be broken. Then in 1895, Wilhelm Röntgen found a strange invisible ray that made a screen glow across the room. He used it to see the bones in his wife's hand. Nobody knew what it was, and the hunt to understand it soon led scientists inside the atom.","minAge":4},{"event":"radioactivity-1896","year":1896,"label":"Becquerel finds radioactivity","emoji":"☢️","link":"X-ray news reached Becquerel in January 1896, and he thought his phosphorescent uranium salts might absorb sunlight and give it back out as X-rays. But the plates fogged clearly even when the uranium had sat in a dark drawer, and he confirmed sunlight was unnecessary: the uranium salts gave off the rays on their own.","kidsLink":"Röntgen's rays made everyone curious. The next year, Henri Becquerel found that uranium gave off its own invisible rays, even sitting in a dark drawer. The energy was coming from the uranium itself.","minAge":4},{"event":"electron-1897","year":1897,"label":"Thomson discovers the electron","emoji":"⚛️","link":"At about the same time, working on cathode rays rather than uranium, J. J. Thomson showed the atom was not indivisible after all: the rays were streams of electrons, particles far smaller than any atom — the first proof that atoms have parts.","kidsLink":"At about the same time in England, J. J. Thomson found tiny particles called electrons, much smaller than any atom. They were the first proof that atoms have smaller parts inside.","minAge":4},{"event":"radium-1898","year":1898,"label":"The Curies discover radium","emoji":"🔬","link":"If uranium gives off rays all by itself, the next questions are whether anything else does and how strongly. The Curies searched pitchblende ore and found two intensely radioactive new elements; radium, thousands of times more radioactive than uranium, became the source physicists reached for to probe the atom.","kidsLink":"Scientists now knew that atoms have parts and that uranium gives off rays. In 1898 Marie and Pierre Curie found two new elements, polonium and radium. Radium gave off rays thousands of times stronger than uranium, all on its own.","minAge":4},{"event":"relativity","year":1905,"label":"Einstein's miracle year","emoji":"🌌","link":"A sample of radium stays warmer than its surroundings because of the radiation it gives out. Einstein's E = mc² offered a way to account for that: mass and energy are two forms of the same thing, so a body that gives out energy must lose a sliver of its mass, and Einstein himself suggested radium salts to test it.","kidsLink":"Radium stays a little warmer than the air around it, all by itself. In 1905 Albert Einstein wrote down a famous rule, E = mc². It says mass and energy are really the same thing, so a tiny bit of mass can become energy.","minAge":4},{"event":"rutherford-s-atomic-nucleus","year":1911,"label":"Rutherford's Atomic Nucleus","emoji":"⚛️","link":"Radium and its decay products give off alpha particles, so Rutherford's team used them as bullets to probe the inside of an atom. A few bounced back off gold foil at large angles, which made sense only if the atom's positive charge and most of its mass sat in a tiny, dense core: the nucleus.","kidsLink":"Einstein showed that a tiny bit of mass can turn into energy. A few years later, Ernest Rutherford's team fired tiny particles at gold foil. They found that most of an atom's mass is packed into one tiny center, called the nucleus.","minAge":4},{"event":"chadwick-discovers-the-neutron","year":1932,"label":"Chadwick Discovers the Neutron","emoji":"⚛️","link":"The nucleus still hid a long-standing puzzle about atomic mass, and Chadwick solved it with a particle that had mass but no charge. Because a neutron carries no charge, it does not have to fight the nucleus's electric repulsion to reach it, which handed physics an ideal tool for reaching the core.","kidsLink":"Rutherford found the nucleus at the center of the atom, but its mass was still a puzzle. In 1932, James Chadwick solved it: a new particle with no electric charge, the neutron, was hiding inside it too.","minAge":4},{"event":"cockcroft-and-walton-split-the-atom","year":1932,"label":"Cockcroft and Walton Split the Atom","emoji":"💥","link":"Chadwick's neutral particle was one way into the nucleus that same year; Cockcroft and Walton found another. Firing protons from a machine they had built themselves, they split a lithium nucleus: the first artificial nuclear reaction driven entirely by man-made technology.","kidsLink":"That same year, two other scientists, John Cockcroft and Ernest Walton, tried something new. They built a machine that fired tiny particles at lithium and broke its nucleus apart. It was the first atom ever split by a machine that people built.","minAge":4},{"event":"fermi-slow-neutrons-1934","year":1934,"label":"Fermi discovers the power of slow neutrons","emoji":"⚛️","link":"Cockcroft and Walton had shown a machine could split a nucleus; Fermi went after a different tool entirely. In 1934 he bombarded element after element with neutrons, and found that slowing them down first, by passing them through wax, made other atoms capture them far more easily.","kidsLink":"Cockcroft and Walton had just split an atom using a machine. In 1934, Enrico Fermi tried something different: firing neutrons at atoms. He found that slowing the neutrons down with wax made other atoms catch them much more easily.","minAge":4},{"event":"nuclear-fission-1938","year":1938,"label":"Nuclear fission discovered","emoji":"⚛️","link":"Labs in Rome and Paris fired the new neutrons at uranium, and Fermi concluded he had made new, heavier elements. In Berlin, Hahn and Strassmann found barium instead, with an atomic mass 40% less than uranium's, and no known kind of radioactive decay could explain such a big drop.","minAge":10},{"event":"lise-meitner-nuclear-fission","year":1938,"label":"Lise Meitner Explains Nuclear Fission","emoji":"⚛️","link":"Hahn wrote with the baffling result to his long-time partner Lise Meitner, who had escaped Nazi Germany that July. In Sweden that Christmas, on a tree trunk with her nephew Otto Frisch, she worked it out on scraps of paper: the nucleus had split, and the mass lost matched the energy released, as E = mc² says.","minAge":10},{"event":"paris-team-counts-fission-neutrons-1939","year":1939,"label":"Counting the spare neutrons in Paris","emoji":"🔢","link":"Meitner and Frisch had shown a nucleus could split and release energy, but a chain reaction needs each split to hand on more than one neutron. In April 1939 a Paris team measured it directly — reporting about 3.5 spare neutrons per fission, proof there were neutrons enough to spare.","minAge":10},{"event":"einstein-szilard-letter-1939","year":1939,"label":"The letter Einstein signed","emoji":"✉️","link":"With neutrons to spare, a chain reaction looked possible. Szilárd drafted a warning that it might make 'extremely powerful bombs of a new type', and that Germany had stopped selling uranium from Czechoslovak mines it had taken. Einstein signed it; delivered on 11 October, it led to Roosevelt's uranium committee.","minAge":10},{"event":"manhattan-project-created-1942","year":1942,"label":"The Manhattan Project","emoji":"🏭","link":"Roosevelt's uranium committee was only a start. On 13 August 1942 the US Army created the Manhattan Engineer District, the Manhattan Project, a secret effort that grew to nearly 130,000 people at sites like Oak Ridge, Hanford and Los Alamos, all to build working bombs.","minAge":13},{"event":"chicago-pile-1","year":1942,"label":"The first nuclear reactor","emoji":"☢️","link":"The new Manhattan Project needed proof that a chain reaction could actually be started and controlled. Under the stands of a Chicago sports field, Fermi's team stacked graphite and uranium until the reaction sustained itself, and showed they could stop it again with a cadmium control rod.","minAge":10},{"event":"trinity-test-first-nuclear-detonation","year":1945,"label":"Trinity Test: First Nuclear Detonation","emoji":"☢️","link":"Chicago Pile-1 showed a chain reaction could be started and controlled; the Manhattan Project was built to make one run away on purpose. In the New Mexico desert it finally tested a working device, the first nuclear detonation, just weeks before it was used in war.","minAge":10},{"event":"hiroshima-nagasaki-1945","year":1945,"label":"Atomic bombs on Hiroshima and Nagasaki","emoji":"☢️","link":"Trinity proved the design worked. Within weeks, in August 1945, the United States dropped atomic bombs on Hiroshima and Nagasaki, killing well over a hundred thousand people. The same chain reaction that Fermi held steady in Chicago was now used as a weapon.","minAge":13},{"event":"ebr-1-nuclear-electricity","year":1951,"label":"Atoms light four bulbs","emoji":"💡","link":"The same chain reaction that destroyed two cities could also be run gently, held exactly at its balance point, to make nothing more dramatic than heat. In December 1951, the experimental EBR-I reactor in Idaho became one of the first to turn that heat into electricity, famously lighting four bulbs.","kidsLink":"Later, scientists found that when some atoms catch a neutron, they split in two and give off heat. In 1951 a test reactor in Idaho used that heat to make electricity, one of the first ever to do so. It lit up four light bulbs.","minAge":4},{"event":"atoms-for-peace-1953","year":1953,"label":"Atoms for Peace","emoji":"🕊️","link":"EBR-I had just shown atomic heat could make electricity, yet to most people the atom still meant the bomb. In December 1953 Eisenhower told the UN that man's inventiveness should be 'consecrated to his life'; the Atoms for Peace programme that followed sent nuclear equipment to schools, hospitals and research labs.","minAge":10},{"event":"obninsk-nuclear-power","year":1954,"label":"The first nuclear power station on the grid","emoji":"🏭","link":"Run under control, the reaction simply makes heat, and heat is all any power station needs: boil water, spin a turbine. Twelve years after the pile and three years after an American test reactor lit four light bulbs, a small Soviet reactor at Obninsk became the first to send that heat to a public grid as electricity.","kidsLink":"A test reactor in Idaho lit four light bulbs using heat from atoms. Three years later, a small power plant at Obninsk in the Soviet Union went further. It sent electricity onto a real public power grid — the first reactor ever to do that.","minAge":4},{"event":"calder-hall-opens-1956","year":1956,"label":"Calder Hall: nuclear power becomes an industry","emoji":"🔌","link":"Obninsk had proven a reactor could feed a grid, but at just 5 megawatts. In October 1956 Britain's Calder Hall opened as the first full-scale nuclear power station, each of its reactors putting out roughly ten times Obninsk's output, though its true job was making plutonium for bombs.","minAge":10},{"event":"shippingport-atomic-power-station","year":1957,"label":"Shippingport Goes Civilian","emoji":"⚡","link":"Calder Hall had proven nuclear electricity could run at scale, but its true job was making plutonium for bombs. A year later Shippingport, built from a design meant for a cancelled nuclear warship, went the other way: the US calls it the first full-scale plant built purely for peaceful power.","kidsLink":"Obninsk was the first to send nuclear electricity onto a public power grid. In 1957 the United States built its own plant just for making power, called Shippingport. It reused a design first meant for a warship, but this time it only made electricity for people.","minAge":7},{"event":"nuclear-non-proliferation-treaty-1968","year":1968,"label":"The Non-Proliferation Treaty","emoji":"📜","link":"Shippingport showed civilian power could be built apart from weapons, but the two still shared the same uranium and know-how, spreading worldwide since Atoms for Peace. In 1968 the Non-Proliferation Treaty made that separation a global bargain: peaceful technology in exchange for a promise never to build the bomb.","minAge":10},{"event":"messmer-plan-1974","year":1974,"label":"Oil shock launches France's nuclear fleet","emoji":"🏗️","link":"The Non-Proliferation Treaty had just drawn a legal line between power and weapons, but oil, not politics, set off France's nuclear building spree. In answer to the 1973 oil crisis, its government launched a huge programme in 1974 that built 56 reactors in fifteen years, cutting its reliance on imported oil.","kidsLink":"The United States built Shippingport just to make electricity, not weapons. Years later, an oil crisis in 1973 worried France, which burned imported oil for much of its power. So in 1974 France decided to build dozens of nuclear reactors instead.","minAge":4},{"event":"three-mile-island-s-nuclear-meltdown","year":1979,"label":"Three Mile Island's Partial Meltdown","emoji":"☢️","link":"By the late 1970s reactors were going up in many countries, France's crash programme among them, and nuclear power felt routine. That confidence cracked in 1979, when a stuck valve and operator errors caused a partial meltdown at Three Mile Island in Pennsylvania, the worst accident in US commercial nuclear history.","kidsLink":"Nuclear power stations were being built in many countries. Then in 1979, a stuck valve and some mistakes caused part of a reactor to melt at Three Mile Island in the US. Nobody's health was harmed, but people became much more worried about nuclear power.","minAge":7},{"event":"chernobyl-1986","year":1986,"label":"Chernobyl disaster","emoji":"☢️","link":"Seven years after Three Mile Island came far worse. In 1986 a reactor explosion at Chernobyl, in Soviet Ukraine, spread radiation across the Soviet Union and Europe: the most destructive nuclear disaster in history, and a big part of why nuclear power is still argued over.","minAge":10},{"event":"qinshan-nuclear-power-plant-china","year":1991,"label":"Qinshan: China's First Nuclear Plant","emoji":"🏗️","link":"Chernobyl had just shown the worst nuclear power could do, yet China pressed on. In December 1991 it connected Qinshan, its first home-designed nuclear plant, built almost entirely with domestic technology, the start of a build-out that by September 2026 had 39 more reactors under construction.","kidsLink":"Not every country gave up on nuclear power after Three Mile Island. In 1991, China switched on its first nuclear power station, at Qinshan. China designed and built it almost all by itself.","minAge":4},{"event":"fukushima-2011","year":2011,"label":"Fukushima disaster","emoji":"☢️","link":"While China's fleet kept growing, the risk that had worried people since Chernobyl had not gone away. In March 2011 an earthquake and tsunami knocked out cooling at Japan's Fukushima Daiichi plant and reactor fuel melted, regarded by the UN's radiation committee as the worst nuclear accident since Chernobyl.","minAge":10},{"event":"nuclear-fusion-energy-gain","year":2022,"label":"Nuclear Fusion Energy Gain","emoji":"⚡","link":"Every reactor in this story, Chernobyl and Fukushima included, grew from fission, splitting heavy nuclei apart. Fusion is the opposite process, joining nuclei together as the Sun does with hydrogen, and in 2022 U.S. scientists finally got a fusion reaction to release more energy than the lasers delivered to start it.","kidsLink":"Meanwhile, scientists had long been working on another way to get energy from atoms. It is called fusion, and it is how the Sun makes its energy. In 2022 they made a fusion reaction give out more energy than the lasers put into it.","minAge":4},{"event":"germany-nuclear-exit-cop28-2023","year":2023,"label":"Germany exits nuclear; COP28 pledges to triple","emoji":"🌐","link":"Fusion's 2022 breakthrough is still a long way from a power plant, so the argument over today's fission reactors kept going. In 2023 the split showed clearly: Germany shut its last three reactors in April, while that December 25 countries at COP28 pledged to triple nuclear capacity by 2050.","kidsLink":"Fusion works in a lab, but it is not ready to power homes yet. So in 2023 countries still disagreed about today's nuclear power. Germany switched off its last reactors, while 25 other countries promised to try to triple nuclear power by 2050.","minAge":4}]},{"id":"human-rights-through-time","title":"What a person is owed","emoji":"⚖️","blurb":"The long argument over what a person is owed simply for being one - an argument that has been won, lost, and had to be won all over again.","minAge":13,"kidsCut":true,"lens":"power","group":"people-and-ideas","beats":[{"event":"code-of-hammurabi","year":-1753,"label":"Code of Hammurabi","emoji":"⚖️","link":"Start where the question starts: one of the earliest written attempts to say, in public, what power may do to you. Hammurabi's stone fixed penalties for all to see, though not equally for all - the penalty depended on who you were.","kidsLink":"This is where the story starts. A king named Hammurabi carved his laws into stone, so everyone could see the rules and the punishments.","minAge":4},{"event":"cyrus-cylinder","year":-539,"label":"The Cyrus Cylinder","emoji":"📜","link":"Hammurabi's code set out laws for one kingdom; after taking Babylon in 539 BCE, Cyrus the Great had a cylinder buried that says he sent deported peoples home. Iran's last Shah called it the first charter of human rights; the British Museum calls it ancient propaganda.","minAge":10},{"event":"mencius-goodness-of-human-nature","year":-300,"label":"Mencius argues that people are born good","emoji":"🌱","link":"Written law told people what could be done to them; it said nothing about what they could do about it. In China, Mencius supplied an answer - people have an inborn pull towards goodness, and a ruler who ignores their needs and rules harshly loses the right to rule.","kidsLink":"Hammurabi's laws said what a ruler could do to you. Mencius asked a different question: what happens if the ruler is the one doing wrong?","minAge":4},{"event":"ashoka-kalinga-edicts","year":-260,"label":"Ashoka renounces war","emoji":"🦁","link":"Mencius argued a harsh ruler loses the right to rule; Ashoka is a ruler who restrained himself. After the bloody conquest of Kalinga he wrote of his remorse and carved edicts of tolerance and the renunciation of war across his realm - a promise from above, not something his subjects could claim.","minAge":10},{"event":"constitution-of-medina","year":622,"label":"Constitution Of Medina","emoji":"🕌","link":"An emperor's conscience dies with the emperor. The agreement drawn up at Medina did something sturdier: it bound Muslim, Jewish and pagan clans to each other in writing, with mutual duties - rights as a condition of belonging to a community rather than a gift from one man's mood.","kidsLink":"Mencius said a bad ruler could lose his right to rule. In Medina, Muhammad wrote down rules that different groups agreed to follow together.","minAge":4},{"event":"magna-carta","year":1215,"label":"Magna Carta","emoji":"📃","link":"Medina bound a community's members to each other by shared duties; Magna Carta bound the ruler himself. Rebel English barons pressed King John to seal a charter limiting what the Crown could demand and promising protection from illegal imprisonment - words invoked against the divine right of kings centuries later.","minAge":10},{"event":"the-manden-charter","year":1236,"label":"The Manden Charter, spoken not written","emoji":"⚖️","link":"Magna Carta was pressed on a king by his barons; in Mali, oral tradition says the new empire's clans met at Kurukan Fuga to agree how to live together. Griots handed it down: the charter quoted today, which keeps castes and slaves, was written down in 1998, and a hunters' oath, 'every life is a life', in 1965.","minAge":10},{"event":"las-casas-valladolid-debate","year":1550,"label":"Las Casas defends the Indigenous at Valladolid","emoji":"⚖️","link":"Almost every step so far settled what a community's own members owe each other. Empire forced the harder question - whether outsiders counted at all. At Valladolid, Las Casas argued Native Americans could reason and should not be enslaved or converted by force, against Sepúlveda's claim that some were 'natural slaves'.","minAge":10},{"event":"habeas-corpus-act","year":1679,"label":"Habeas Corpus Act","emoji":"🔓","link":"Arguing about who counts is academic if the state can simply take you and hold you. Magna Carta had promised protection from illegal imprisonment; the 1679 Habeas Corpus Act strengthened a detainee's right to be brought before a court, guarding against unlawful and indefinite imprisonment.","kidsLink":"The Medina agreement wrote down how groups should treat each other. Centuries later, a new English law made an old rule stronger: anyone locked up had the right to be brought before a court.","minAge":4},{"event":"locke-two-treatises-1689","year":1689,"label":"Locke says government needs our consent","emoji":"📜","link":"Habeas corpus protected a prisoner in practice; Locke asked why anyone has such protection at all. His answer: people are born with natural rights to life, liberty and property, and a government rules justly only with their consent.","kidsLink":"The Habeas Corpus law protected people who were locked up. Locke asked why: he said people are born with rights, and a government needs its people to agree to it.","minAge":4},{"event":"english-bill-of-rights","year":1689,"label":"English Bill Of Rights","emoji":"📃","link":"Locke argued from principle that government needs consent; in the same year Parliament limited the crown in practice. Its Bill of Rights fixed free elections and free speech in Parliament, and banned cruel and unusual punishments.","kidsLink":"Locke said a government needs its people to agree. In the same year, England's Bill of Rights limited what the king or queen could do and banned cruel punishments.","minAge":4},{"event":"virginia-declaration-of-rights-1776","year":1776,"label":"Virginia Declaration of Rights","emoji":"📜","link":"The Bill of Rights bound one Parliament and crown; Mason's Virginia Declaration, adopted 12 June 1776, grounded rights in the person, holding life and liberty inherent and government answerable to the people. The Declaration of Independence drew on it that month; Madison built on it for the US Bill of Rights.","kidsLink":"England's Bill of Rights had limited one king. In 1776, Virginia wrote down that everyone has rights like freedom, just for being a person - and this idea helped shape the United States' own laws.","minAge":4},{"event":"rights-of-man-declared","year":1789,"label":"Rights Of Man Declared","emoji":"🇫🇷","link":"Virginia spoke for one American state; in 1789 France's assembly made the far larger claim that men are born and remain free and equal in rights. Yet only men who paid enough tax counted as 'active' citizens, and it left slavery standing in the French colonies.","kidsLink":"Virginia said people are born with rights. A few years later in France, a new assembly declared the same idea for their whole country: that men are born free and equal in rights.","minAge":4},{"event":"olympe-de-gouges-rights-declaration","year":1791,"label":"Olympe de Gouges' Rights Declaration","emoji":"📜","link":"The word in the title was 'Man', and women noticed. In 1791 Olympe de Gouges answered it with a Declaration of the Rights of Woman and of the Female Citizen - and in 1793 the Revolution guillotined her for her political writings, a stark reminder that a declaration and a right are not the same thing.","minAge":13},{"event":"haitian-constitution-of-1801","year":1801,"label":"Saint-Domingue's constitution abolishes slavery forever","emoji":"📜","link":"Argument was one way to test a declaration; revolt was the other. France's declaration had left slavery standing in its colonies, and in Saint-Domingue the enslaved rose up in 1791. A decade later Louverture's constitution declared servitude 'forever abolished' - and Napoleon sent 20,000 men to restore French rule.","minAge":10},{"event":"slavery-abolition-act-1833","year":1833,"label":"Slavery Abolished Across the British Empire","emoji":"🕊️","link":"Haiti proved the enslaved could seize freedom by force; Britain took the slower route, outlawing the Atlantic slave trade in its empire in 1807, then in 1833 freeing roughly 800,000 people by Act of Parliament - though many were pushed into further unpaid 'apprenticeship' first.","minAge":10},{"event":"seneca-falls-1848","year":1848,"label":"Seneca Falls Convention","emoji":"♀️","link":"Abolition fed women's rights: at the 1840 World Anti-Slavery Convention, women could listen but not speak or vote; Mott and Stanton met there and planned their own convention. At Seneca Falls in 1848 its declaration, modelled on the Declaration of Independence, said 'all men and women are created equal'.","kidsLink":"France had said men are born equal. In 1848, women in the United States met and said women deserved equal rights too, including the right to vote.","minAge":4},{"event":"russia-abolishes-serfdom","year":1861,"label":"Russia Abolishes Serfdom","emoji":"🌾","link":"Seneca Falls demanded rights for women; in 1861 Tsar Alexander II's Emancipation Manifesto freed more than 23 million privately owned serfs in Russia - though peasants had to buy their land through redemption payments spread over 49 years, and the state's serfs waited until 1866.","minAge":10},{"event":"first-geneva-convention-protects-war-s-wounded","year":1864,"label":"First Geneva Convention Protects War's Wounded","emoji":"➕","link":"Russia had just freed serfs from bondage in peacetime; the Geneva Convention, inspired by Henry Dunant's book A Memory of Solferino and signed by 12 states in 1864, extended a duty of care into war itself - care for wounded soldiers of every side, and protection for those who helped them.","minAge":10},{"event":"thirteenth-amendment-abolishes-us-slavery","year":1865,"label":"Thirteenth Amendment Abolishes US Slavery","emoji":"⛓️‍💥","link":"Geneva had bound nations to protect wounded enemies; on 6 December 1865 the United States ratified the Thirteenth Amendment, abolishing slavery and involuntary servitude nationwide except as punishment for crime.","minAge":10},{"event":"brazil-abolishes-slavery","year":1888,"label":"Brazil Abolishes Slavery","emoji":"🕊️","link":"The Thirteenth Amendment ended slavery in the United States in 1865; Brazil held out over twenty years longer. In 1888 Princess Isabel's Golden Law freed its remaining enslaved people, about 600,000 by one estimate - Brazil was the last country in the Americas to abolish slavery.","minAge":10},{"event":"new-zealand-becomes-first-nation-with-women-s-vo","year":1893,"label":"New Zealand Becomes First Self-Governing Nation With Women's Vote","emoji":"🗳️","link":"Brazil was the last country in the Americas to abolish slavery. Five years later, after campaigners led by Kate Sheppard presented a petition of nearly 32,000 signatures, New Zealand's Electoral Act 1893 made it the first self-governing country where women could vote in parliamentary elections.","minAge":10},{"event":"nuremberg-laws-1935","year":1935,"label":"The Nuremberg Laws strip citizenship","emoji":"⚖️","link":"The century's hardest lesson was that rights a state writes down, a state can withdraw. The Nuremberg Laws of 1935 declared that only people of 'German or related blood' could be Reich citizens; once the law took effect, German Jews were no longer citizens and lost the right to vote.","minAge":13},{"event":"un-founded-1945","year":1945,"label":"The United Nations","emoji":"🕊️","link":"The Nuremberg Laws showed how far a state could strip its own people of standing. In 1945, fifty nations founded the United Nations to prevent another world war - and its Charter named 'promoting and encouraging respect for human rights' among its purposes.","kidsLink":"In 1848, women in the United States said women deserved equal rights too. Much later, after a terrible world war, fifty countries formed the United Nations in 1945 to try to keep the peace and stand up for people's rights.","minAge":4},{"event":"nuremberg-verdicts-crimes-against-humanity","year":1946,"label":"Nuremberg Verdicts: 'Crimes Against Humanity'","emoji":"⚖️","link":"The Nuremberg Laws were a state's laws against its own people. On 1 October 1946, in the same city, the International Military Tribunal convicted senior Nazi leaders of 'crimes against humanity' - a charge that was new in international law.","minAge":13},{"event":"un-adopts-the-universal-declaration-of-human-rig","year":1948,"label":"UN Adopts The Universal Declaration Of Human Rights","emoji":"🕊️","link":"Nuremberg punished crimes after the fact; there was still no written list of what every person is owed. The Universal Declaration, drafted by a committee chaired by Eleanor Roosevelt with members from China, France and Lebanon, set one out - adopted with eight abstentions, and not legally binding.","kidsLink":"The United Nations wanted to protect rights, but had not yet said which ones. In 1948, it wrote them down in the Universal Declaration of Human Rights.","minAge":4},{"event":"un-genocide-convention-adopted","year":1948,"label":"UN Adopts the Genocide Convention","emoji":"🕊️","link":"The Declaration was not legally binding; the day before its adoption on 10 December 1948, the same General Assembly adopted the Genocide Convention, which did bind - turning Raphael Lemkin's new word into international law and obliging states to prevent and punish genocide, not only judge it afterwards.","minAge":13},{"event":"india-constitution-abolishes-untouchability","year":1950,"label":"India's Constitution Abolishes Untouchability","emoji":"📜","link":"The Genocide Convention was written for the whole world; India's constitution, taking effect in 1950, looked at home, legally abolishing untouchability - the shunning of Dalits from wells, temples and public life - and setting out affirmative action in education and public services.","minAge":10},{"event":"european-convention-human-rights-1950","year":1950,"label":"Europe signs a convention with teeth","emoji":"📜","link":"The same year, India's constitution tackled rights at home; Europe worked the same problem across borders. The Declaration had promised rights but offered no remedy, so two years later the Council of Europe's members signed a convention with real machinery - a commission, and later a court that could rule against a government.","kidsLink":"The Universal Declaration listed rights for everyone, but had no way to make countries follow them. Two years later, European countries signed an agreement that later came with a real court to check on them.","minAge":4},{"event":"refugee-convention-1951","year":1951,"label":"The Refugee Convention and a rule no state may opt out of","emoji":"🛂","link":"Europe had just signed a convention for rights at home; in July 1951 a UN conference in Geneva finished one for people whose own state could no longer protect them - refugees - anchored on one rule, non-refoulement: no state may return a refugee to persecution.","minAge":10},{"event":"year-of-africa","year":1960,"label":"The Year of Africa","emoji":"🌍","link":"The Refugee Convention answered what a state owed people fleeing across its borders; Europe still ruled the peoples inside its colonial ones. In 1960 seventeen African nations won independence in a single year, and on 14 December the UN declared foreign rule a violation of human rights.","minAge":10},{"event":"civil-rights-act-1964","year":1964,"label":"U.S. Civil Rights Act","emoji":"⚖️","link":"The Year of Africa ended foreign rule abroad; in 1964 the United States confronted unequal rule at home, when the Civil Rights Act outlawed segregation and discrimination based on race, colour, religion, sex or national origin.","minAge":10},{"event":"two-human-rights-covenants-1966","year":1966,"label":"The Declaration is written into binding law — twice","emoji":"📖","link":"The US had just outlawed discrimination by its own law; in 1966 the UN General Assembly turned the Universal Declaration itself into treaty law, binding once enough states ratified in 1976 - split into two covenants, civil-political and economic-social, because members could not agree which rights mattered most.","kidsLink":"Europe had built its own court for rights. In 1966, the United Nations turned its big list of rights into real rules for the countries that signed up to follow them.","minAge":4},{"event":"un-adopts-global-treaty-against-sex-discriminati","year":1979,"label":"UN Adopts Global Treaty Against Sex Discrimination","emoji":"🕊️","link":"The 1966 covenants bound states to rights in general terms; women still needed a treaty spelling out what equality meant for them. In 1979 the UN adopted CEDAW, called an international bill of rights for women, committing countries to end discrimination in law, education, employment and politics.","minAge":10},{"event":"un-adopts-the-convention-on-the-rights-of-the-ch","year":1989,"label":"UN Adopts The Convention On The Rights Of The Child","emoji":"🧒","link":"CEDAW had spelled out what equality meant for women; a decade later, in 1989, the UN adopted the Convention on the Rights of the Child, the most ratified human rights treaty in history, reframing children as rights-holders owed education, a hearing and protection rather than mere objects of it.","kidsLink":"In 1966, countries agreed to follow rules protecting everyone's rights. In 1989, the United Nations wrote down special rights just for children, like the right to learn, to be heard and to be kept safe.","minAge":4},{"event":"south-africa-election-1994","year":1994,"label":"South Africa's First Free Election","emoji":"🗳️","link":"Treaties kept asking states to write equality into their own law; South Africa still lived under apartheid. Between 26 and 29 April 1994 South Africans of all races voted in a national election for the first time, and the new National Assembly elected Nelson Mandela the country's first Black president.","minAge":10},{"event":"rome-statute-adopted-1998","year":1998,"label":"Rome votes for a permanent war-crimes court","emoji":"🏛️","link":"Nuremberg's tribunal judged the leaders of one regime. In 1998, 120 countries voted in Rome for a permanent International Criminal Court to try individuals for genocide, crimes against humanity, war crimes and aggression - though the United States, Russia and China never joined it.","minAge":13},{"event":"netherlands-marriage-2001","year":2001,"label":"Netherlands: First Same-Sex Marriages","emoji":"💍","link":"Rome dealt with the worst crimes; the next step came closer to everyday life. In 2001 the Netherlands became the first country in the world to let same-sex couples legally marry, with the first weddings held in Amsterdam.","kidsLink":"In 1989, children got their own special rights. In 2001, the Netherlands became the first country in the world to let same-sex couples get married.","minAge":4},{"event":"crpd-2006","year":2006,"label":"UN Convention on the Rights of Persons with Disabilities","emoji":"♿","link":"The Netherlands had just widened who could marry; in 2006 the UN widened whose rights were spelled out by name, adopting a convention affirming that people with disabilities have the same rights to education, work and full participation in society as everyone else.","kidsLink":"In 2001, the Netherlands let more couples get married. In 2006, the United Nations said people with disabilities have exactly the same rights as everyone else.","minAge":4},{"event":"undrip-2007","year":2007,"label":"UN Declaration on the Rights of Indigenous Peoples","emoji":"🪶","link":"2006 had widened rights to a group defined by disability; 2007 widened the unit itself, from individuals to whole peoples - land, language, self-determination. Australia, Canada, New Zealand and the United States voted against the declaration, and all four have since reversed and now support it.","kidsLink":"In 2006, the United Nations protected the rights of people with disabilities. In 2007, it wrote down special rights for Indigenous peoples too, saying their lands and cultures deserve respect.","minAge":4},{"event":"un-recognises-right-to-healthy-environment-2022","year":2022,"label":"A Healthy Environment Becomes a Human Right","emoji":"🌳","link":"UNDRIP widened whose rights counted, from individuals to peoples; 2022 widened what counts as a right, declaring a clean, healthy environment one itself. Passed by the General Assembly on 28 July, it isn't legally binding - like the 1948 Declaration, it states an aim before any court can enforce it.","kidsLink":"The 2007 declaration protected Indigenous peoples' lands. In 2022, the United Nations said every person has the right to live in a clean, healthy world.","minAge":4}]},{"id":"what-makes-us-sick","title":"How we learned what makes us sick","emoji":"🦠","blurb":"The long road from \"the gods made you ill\" to naming the germs, the missing foods and the smoke behind disease — and to reading a brand-new virus's genes within days.","minAge":13,"kidsCut":true,"lens":"science","group":"food-and-health","beats":[{"event":"edwin-smith-surgical-papyrus","year":-1600,"label":"Edwin Smith Surgical Papyrus","emoji":"📜","link":"Start here: before anyone could explain illness, someone had to write down what they observed. This Egyptian scroll, likely copied from a much older original, sets out the examination, diagnosis and treatment of 48 injuries in a rational way that avoids prescribing magic.","kidsLink":"This is where our story begins. Long before anyone knew what caused sickness, Egyptian doctors wrote down what they saw when someone got hurt, and worked out how to help.","minAge":7},{"event":"uzziah-tzaraath","year":-751,"label":"Uzziah is struck with a skin disease","emoji":"👑","link":"Egypt's physicians could treat an injury by observation, but the Bible tells a different kind of story about why someone fell sick. Centuries later King Uzziah of Judah was struck with a skin disease, tzaraath, the moment he defied the priests to burn incense in the Temple, and had to live apart in 'a separate house'.","kidsLink":"Egyptian doctors could treat what they saw. Much later, King Uzziah got a skin sickness. The Bible says it struck him when he broke a Temple rule, and he had to live away from the palace.","minAge":7},{"event":"hippocrates-and-medicine","year":-461,"label":"Hippocrates And Medicine","emoji":"⚕️","link":"Three centuries later a Greek school made a radical claim: diseases have natural causes, not divine ones. The instinct was right; the mechanism (an imbalance of the body's four humours, or fluids) was wrong, and was disproved only with the discovery of microbes. Yet Galen's views, built on it, would dominate Western medicine for more than 1,300 years.","kidsLink":"Uzziah's sickness was seen as a punishment. Centuries later, Hippocrates said something new. He said sickness has natural causes, not gods.","minAge":4},{"event":"huangdi-neijing","year":-300,"label":"The Yellow Emperor's Inner Canon","emoji":"🪡","link":"Hippocrates was not alone in seeking natural causes. In China, physicians compiled the Huangdi Neijing, the foundation of traditional Chinese medicine, which explains health with a different natural framework: the balance of yin and yang and qi.","kidsLink":"Hippocrates was not the only one with this idea. In China, doctors wrote their own book, saying health comes from balancing yin, yang and body energy.","minAge":4},{"event":"charaka-samhita-ayurveda","year":100,"label":"Charaka and the science of Ayurveda","emoji":"🌿","link":"A third tradition took shape in India: the Charaka Samhita, a foundational text of Ayurveda, set out its own way to diagnose disease, prepare herbal remedies and live for health, urging doctors to observe carefully and treat with compassion.","kidsLink":"China was not the only place with its own medical ideas. In India, doctors wrote the Charaka Samhita, teaching their own way to understand sickness and treat patients kindly.","minAge":4},{"event":"galen-of-pergamon","year":170,"label":"Galen, doctor to the gladiators","emoji":"🩹","link":"Rome's medicine followed the Greek line Hippocrates began. Galen, who first treated wounded gladiators, drew principally on the theory of the four humours, and his writings ruled European and Islamic medicine for over a thousand years, even where later study proved him wrong.","kidsLink":"India had its own medical ideas. But in Rome, a doctor named Galen built on the old Greek idea of the body's four humours, and his writings were the rule for doctors for over a thousand years.","minAge":7},{"event":"avicenna-canon-1025","year":1025,"label":"Avicenna's Canon of Medicine","emoji":"⚕️","link":"Galen's system did not stay in Rome: his tradition had dominated Islamic medicine from its beginnings. The Persian polymath Avicenna (Ibn Sina) built his five-book Canon of Medicine on the four humours, and it became a standard medical textbook in the Islamic world and Europe for centuries.","kidsLink":"Galen's ideas spread far past Rome. Centuries later, a doctor named Avicenna wrote a huge five-book medical guide. Doctors across Europe and the Islamic world used it for hundreds of years.","minAge":4},{"event":"black-death","year":1347,"label":"The Black Death","emoji":"🐀","link":"Avicenna's Canon, built on the four humours, was still a standard textbook when plague, carried on Genoese ships from the Black Sea, reached Europe in 1347 and within a few years killed an estimated 30–60% of its people: a disease that came by ship.","minAge":10},{"event":"first-quarantine-law","year":1377,"label":"Ragusa makes ships wait out the plague","emoji":"⛵","link":"Plague had come by ship. Ragusa's answer was practical, not theoretical: a 1377 decree made newcomers spend 30 days in isolation, first on nearby islands, to see whether they carried the plague before entering. Venice later stretched the wait to 40 days, which gave us the word quarantine.","kidsLink":"Long after Avicenna, the city of Ragusa tried a new way to stop sickness spreading. Visitors had to wait 30 days away from everyone, to see if they were ill.","minAge":7},{"event":"fracastoro-proposes-a-theory-of-contagion","year":1546,"label":"Fracastoro Proposes a Theory of Contagion","emoji":"🦠","link":"Quarantine kept travellers apart without explaining how disease passed between people. Nearly two centuries later Fracastoro proposed a mechanism: epidemic diseases spread through tiny invisible 'seeds' passed by touch, by things like clothes, or even at a distance, a forerunner of germ theory.","kidsLink":"Ragusa kept visitors apart, but that did not explain how sickness spread. Girolamo Fracastoro had a guess. He said disease spreads through tiny invisible 'seeds.' His idea is seen as an early step toward germ theory.","minAge":7},{"event":"wan-quan-writes-down-variolation","year":1549,"label":"China writes down how to give someone smallpox","emoji":"👃","link":"Fracastoro's seeds were a theory of how disease passes between people. In China, at about that time, doctors used that passing on purpose: they blew powdered scabs from a mild smallpox case up a healthy child's nose, hoping for a small illness instead of a deadly one. Wan Quan's 1549 handbook is the earliest clear account.","kidsLink":"Fracastoro guessed that sickness spreads by tiny seeds. Far away in China, doctors blew powder from a mild smallpox scab into a healthy child's nose. They hoped a small illness would keep the child safe from a deadly one.","minAge":7},{"event":"leeuwenhoek-animalcules-1676","year":1676,"label":"Van Leeuwenhoek's 'animalcules'","emoji":"🦠","link":"If sickness passes from person to person, something must be doing the passing. In Delft, a cloth merchant peering through tiny lenses he made himself became the first person to see living bacteria and protozoa, creatures that came to be known in English as 'animalcules'.","kidsLink":"Chinese doctors gave children a little smallpox on purpose to keep them safe. Over a hundred years later, a Dutch cloth seller looked through his homemade lenses. He became the first person to see living bacteria.","minAge":4},{"event":"onesimus-teaches-smallpox-inoculation-in-boston","year":1716,"label":"Onesimus Teaches Smallpox Inoculation in Boston","emoji":"💉","link":"You do not need to see a germ to act on what works. Onesimus, an African man enslaved by Boston minister Cotton Mather, described how he had been inoculated against smallpox in Africa. When smallpox struck Boston in 1721, Mather promoted the method; of 280 people inoculated, only six died.","minAge":10},{"event":"montagu-brings-smallpox-inoculation","year":1721,"label":"Lady Mary brings inoculation to Britain","emoji":"💉","link":"The same practice reached Britain by a second route: Lady Mary Wortley Montagu had seen women in Ottoman Turkey do it, and in April 1721, as a smallpox epidemic struck England, had her daughter inoculated and publicised it. It used real smallpox: 1–2% of those inoculated died, and they could infect others.","kidsLink":"A Dutchman had seen tiny living things. Years later, Lady Mary Wortley Montagu saw something in Turkey. People there gave children a tiny dose of smallpox to protect them. She brought the idea home to England.","minAge":7},{"event":"lind-tests-scurvy-cure","year":1747,"label":"Lind Tests Scurvy Cure","emoji":"🍋","link":"Inoculation was learned by watching what worked. A generation later, aboard HMS Salisbury, naval surgeon James Lind tested cures on purpose in one of the first controlled clinical trials: of twelve sailors with scurvy, those given citrus fruit recovered best, pointing the way to nutritional medicine.","kidsLink":"Lady Mary brought smallpox protection to England. Years later, a doctor named James Lind ran a careful test on sick sailors. The ones who ate citrus fruit got better fastest from a disease called scurvy.","minAge":7},{"event":"jenner-smallpox-vaccine-1796","year":1796,"label":"Jenner's smallpox vaccine","emoji":"💉","link":"Lind's trial pointed to food as medicine; smallpox was the catching kind, and inoculating with real smallpox carried serious risks, including spreading it to others. Jenner found a safer substitute: in 1796 he showed that inoculating a boy with mild cowpox protected him from deadly smallpox.","kidsLink":"James Lind found that the right food could cure a sickness. Doctor Jenner found something different: a mild cow sickness called cowpox could protect people from the much worse smallpox. That was the world's first vaccine.","minAge":7},{"event":"semmelweis-champions-handwashing","year":1847,"label":"Semmelweis Champions Handwashing","emoji":"🧼","link":"Vaccination guarded against one disease, not why mothers died in hospital. In Vienna, one maternity clinic lost about 10% of mothers to childbed fever, the other under 4%. Semmelweis blamed particles doctors carried from the autopsy room; chlorine handwashing cut the deaths, but some doctors were offended.","kidsLink":"Jenner's vaccine protected against one sickness. In Vienna, a doctor named Semmelweis found something else: when doctors washed their hands, far fewer new mothers got sick. But some doctors did not like being told to wash.","minAge":7},{"event":"snow-maps-the-cholera-outbreak","year":1854,"label":"Snow Maps the Cholera Outbreak","emoji":"💧","link":"Semmelweis found his killer by comparing death rates; Snow did it across a London district, mapping cholera deaths until nearly all lay a short distance from the Broad Street pump. The water was the cause, not 'bad air', and the pump handle was removed. Officials later put it back and rejected his theory.","minAge":10},{"event":"pasteur-proves-germ-theory","year":1861,"label":"Pasteur Lays the Groundwork for Germ Theory","emoji":"🧫","link":"Snow could show the water carried something deadly but not what it was. Pasteur's experiments pointed the way: broth in his flasks grew nothing unless living organisms came in from outside, on dust. Microorganisms do not arise out of nothing, and that laid the groundwork for the germ theory of disease.","kidsLink":"Washing hands cut sickness in new mothers. Louis Pasteur showed that tiny germs, too small to see, make things spoil. His work helped show that germs can make people sick too.","minAge":4},{"event":"lister-s-antiseptic-surgery","year":1867,"label":"Lister's Antiseptic Surgery","emoji":"🧴","link":"If microbes make things rot, an open surgical wound is an invitation. Inspired by Pasteur, Lister used carbolic acid to sterilize wounds and instruments, and fewer patients caught infections after surgery, transforming the craft.","kidsLink":"Pasteur's work pointed to tiny germs. A surgeon named Joseph Lister used that idea in the operating room: he cleaned wounds and tools with a special acid to kill germs, making surgery much safer.","minAge":4},{"event":"koch-proves-anthrax-germ-1876","year":1876,"label":"Koch proves a germ causes a disease","emoji":"🦠","link":"Germ theory said microbes cause disease in general; Koch made it specific. In a poorly equipped laboratory he traced anthrax, which was killing livestock and people, to a single kind of bacterium and its tough spores: the first time a specific microbe was linked to a specific disease.","kidsLink":"Lister used chemicals to kill germs during surgery. Robert Koch went further. Working in a simple little lab, he traced anthrax, a disease that made farm animals and people sick, to one kind of germ.","minAge":7},{"event":"koch-identifies-tuberculosis-germ","year":1882,"label":"Koch Identifies Tuberculosis Germ","emoji":"🦠","link":"Six years later Koch turned to a human killer: in Berlin he identified the bacterium that causes tuberculosis, and his methods became the basis of Koch's postulates, the criteria still used to link a germ to a specific disease.","kidsLink":"Koch had traced a disease of farm animals to one germ. Using the same careful method, he then found the tiny germ that causes tuberculosis, a serious lung disease in people.","minAge":7},{"event":"ivanovsky-discovers-the-first-virus","year":1892,"label":"Ivanovsky Discovers the First Virus","emoji":"🦠","link":"Koch's culprits were bacteria. Ivanovsky found that whatever caused tobacco mosaic disease passed straight through a filter fine enough to trap all known bacteria: the first clue that disease could come from something else entirely, a virus.","kidsLink":"Koch found the germs behind some diseases. Then a scientist found something stranger: whatever made tobacco plants sick could slip through a filter that trapped all known bacteria. It was the first clue that viruses exist.","minAge":4},{"event":"ross-links-mosquitoes-to-malaria","year":1897,"label":"Ross Links Mosquitoes to Malaria","emoji":"🦟","link":"Ivanovsky's filter showed a disease agent could slip past every known bacterium. Ross asked a different question: not what causes a disease, but what carries it. He showed mosquitoes transmit malaria, a disease whose very name comes from the Medieval Italian for 'bad air'.","kidsLink":"Ivanovsky found the first clue that viruses exist. Doctor Ronald Ross asked a different question: how does sickness travel? He found that mosquitoes spread the disease malaria.","minAge":7},{"event":"eijkman-links-beriberi-to-diet","year":1897,"label":"Eijkman Links Beriberi to Diet","emoji":"🍚","link":"Ross traced a disease to a carrier. Eijkman suspected an unknown bacterium behind beriberi, but found food instead: laboratory chickens fed polished white rice developed a beriberi-like illness that cleared on unpolished rice, so he reasoned polished rice lacked something the body needed.","kidsLink":"Ross found that mosquitoes spread malaria. Another doctor found that food can matter too. Chickens fed only polished white rice got sick, then got better on unpolished rice.","minAge":7},{"event":"beijerinck-names-the-virus","year":1898,"label":"Beijerinck Names the Virus","emoji":"🦠","link":"Ivanovsky's filter left open what the agent was. Beijerinck repeated his tobacco mosaic experiments and showed the agent could multiply in the living plant. He called it a virus to show it was not a bacterium: a contagious living fluid.","kidsLink":"Back to the tobacco plants. A Dutch scientist showed the sickness-maker was not a bacterium and could multiply inside living plants. He called it a virus.","minAge":7},{"event":"funk-coins-the-word-vitamin","year":1912,"label":"Funk Coins the Word 'Vitamin'","emoji":"🍊","link":"Back to the missing-food thread: Eijkman's chickens suggested polished rice lacked something the body needed. Funk proposed that beriberi and scurvy come from a lack of trace substances in food, and named them \"vitamines\".","kidsLink":"Remember the chickens that got sick on polished rice? Casimir Funk said some diseases happen when food is missing tiny things. He named them vitamines, which became our word vitamin.","minAge":7},{"event":"penicillin-first-clinical-use","year":1941,"label":"Penicillin becomes a real cure","emoji":"💊","link":"Knowing what caused a disease, or how it reached you, did not cure it. In 1928 a mould had appeared to kill bacteria on a contaminated dish in Fleming's lab, but he convinced no one it mattered, largely because penicillin was so hard to isolate. An Oxford team learned to concentrate it, and in 1941 injected it into a dying patient.","kidsLink":"Funk said that missing food can make people sick. But germs needed a cure too. Doctors tried a mould that had killed germs in a lab dish. A very sick man got it and began to get better within a day.","minAge":7},{"event":"doll-hill-smoking-lung-cancer","year":1950,"label":"Doll and Hill link smoking to lung cancer","emoji":"🚬","link":"Penicillin showed a drug could beat an infection; Doll and Hill turned to a different killer, not a germ but a habit. Studying lung cancer patients across twenty London hospitals, they found smoking was the one thing almost all shared, and risk climbed with how much a person smoked.","minAge":10},{"event":"polio-vaccine-1955","year":1955,"label":"The polio vaccine","emoji":"💉","link":"Doll and Hill had shown that careful counting could uncover a hidden cause; it could also prove a protection. In 1952 the US had about 58,000 polio cases and 3,200 deaths. A 1954 field trial of Salk's vaccine eventually involved 1.8 million American children, and on 12 April 1955 it was announced to work.","minAge":10},{"event":"smallpox-eradicated-1980","year":1980,"label":"Smallpox eradicated","emoji":"🩹","link":"Salk's vaccine showed a virus could be beaten by prevention; smallpox eradication took the same idea worldwide. No smallpox drug became available until after it was gone, so the WHO's global campaign relied mainly on vaccination, nearly two centuries after Jenner, until in 1980 smallpox was declared eradicated.","minAge":13},{"event":"marshall-warren-culture-h-pylori","year":1982,"label":"Marshall and Warren find the ulcer germ","emoji":"🦠","link":"A century after Koch, doctors could still miss a germ hiding in plain sight. In Perth, Warren and Marshall grew a spiral bacterium from stomach linings, challenging decades of belief that ulcers came from stress or spicy food — and Marshall drank a broth of it himself to prove it made people sick.","kidsLink":"Doctors had learned that a special mould could cure sick people. Years later, two doctors in Australia found a strange curly germ living in people's stomachs, and showed it could make people sick. Before that, many thought stomach ulcers came from stress or spicy food.","minAge":7},{"event":"montagnier-s-team-identifies-hiv","year":1983,"label":"Montagnier's Team Identifies HIV","emoji":"🔬","link":"Marshall and Warren showed an old disease could hide an undiscovered germ for decades; AIDS was the opposite: a new disease with no known cause, first recognized by the US CDC in 1981. At the Pasteur Institute, Luc Montagnier's team isolated a new virus from an AIDS patient, later confirmed as the cause.","kidsLink":"Marshall and Warren found a hidden germ behind an old sickness. Around the same time, scientists in Paris found a brand-new virus in a sick patient. It was later named HIV, and it caused the illness called AIDS.","minAge":7},{"event":"sars-cov-2-genome-sequenced","year":2020,"label":"SARS-CoV-2's genome sequenced in days","emoji":"🧬","link":"Finding the virus behind AIDS took about two years after the disease was first reported. By 2020 it could take days: a Shanghai team received swabs from a pneumonia outbreak in Wuhan on 3 January, read the new coronavirus's full genetic code by 5 January, and it was published online on 11 January.","kidsLink":"Finding the virus behind AIDS took scientists a couple of years of careful lab work. By 2020, scientists could work much faster: they read the full code of a brand-new virus in only a few days, and shared it with the world.","minAge":7},{"event":"first-mrna-vaccines-are-authorized","year":2020,"label":"First mRNA Vaccines Are Authorized","emoji":"💉","link":"Publishing the genome on 11 January set off an intense research effort to develop a vaccine. By December, Pfizer-BioNTech and Moderna's mRNA vaccines were authorized, the first widespread real-world use of that technology: a vaccine developed in under a year.","kidsLink":"Scientists soon shared the new virus's full code. Because of that head start, doctors approved the first COVID-19 vaccines made with new mRNA technology in under a year.","minAge":7}]},{"id":"where-writing-came-from","title":"Where writing came from","emoji":"✍️","blurb":"From a farmer's clay counting-token to the phone in your pocket: how marks came to stand for things, then sounds, then everything we say — invented again and again around the world, and spread by paper, print and screens.","minAge":4,"kidsCut":true,"lens":"art","group":"people-and-ideas","beats":[{"event":"clay-tokens-mesopotamia","year":-8000,"label":"Clay tokens: early accounting","emoji":"🧮","link":"This is where the story has to start: before anyone thought to draw a word, people needed to remember a number. Farmers in the Near East kept count of their goods with small clay tokens — a small object standing in for a fact.","kidsLink":"This is where our story begins. Long before anyone could write, farmers used little clay shapes to keep track of their goods.","minAge":4},{"event":"cuneiform-is-born","year":-3300,"label":"Cuneiform Is Born","emoji":"📜","link":"Tokens were sealed in hollow clay balls to keep trades honest, sometimes pressed onto the wet surface first, so the owner knew what was inside without breaking it. Pressing tokens onto flat tablets followed, then drawing with a stylus — and once a mark could stand for a token without the token, writing was on its way.","kidsLink":"People kept clay tokens inside a clay ball, and sometimes pressed them on the outside too. Later they pressed the shapes onto flat clay, and then drew them with a stick. That was a start of writing.","minAge":4},{"event":"egyptian-hieroglyphs-emerge-2","year":-3200,"label":"Hieroglyphs: one of the world's first writing systems","emoji":"📜","link":"At almost the same time, Egyptians on the Nile were marking their own signs onto small labels. Scholars still debate whether the idea came from Mesopotamia, but the early dates of the Abydos labels point to Egypt inventing writing on its own.","kidsLink":"At almost the same time, people in Egypt started marking their own picture-signs onto little labels. Experts still argue about whether they came up with writing on their own.","minAge":4},{"event":"paper-made-from-reeds","year":-3000,"label":"Paper Made From Reeds","emoji":"📄","link":"Egypt's scribes found a surface of their own: they sliced the pith of the papyrus plant into strips, pressed them together and dried them into smooth sheets — not true paper yet, but the writing surface that gave paper its name.","kidsLink":"Egyptians also made something new to write on. They sliced papyrus reeds, pressed the strips together and dried them into smooth sheets.","minAge":4},{"event":"the-indus-script-appears","year":-2600,"label":"The Indus Script Appears","emoji":"🪧","link":"Egypt had papyrus and hieroglyphs; far to the east in the Indus Valley, cities were stamping short strings of signs onto seals and pottery — a script that nobody today can read.","kidsLink":"Far away in the Indus Valley, people were stamping little signs onto seals and pots. Nobody has figured out what those signs mean yet.","minAge":4},{"event":"proto-sinaitic-birth-of-the-alphabet","year":-1800,"label":"Proto-Sinaitic — the alphabet is born in the desert","emoji":"✍️","link":"Workers who spoke a Canaanite language, at Egypt's turquoise mines, repurposed a small set of hieroglyphs and made each one stand for a single sound of their own language — the earliest known alphabetic writing, ancestor of many alphabets used today.","kidsLink":"Workers at an Egyptian mine borrowed a few of the hieroglyph pictures and made each one stand for a sound instead. It was one of the very first alphabets.","minAge":4},{"event":"chinese-oracle-bone-script","year":-1250,"label":"Chinese Oracle Bone Script","emoji":"🐢","link":"Centuries later and far to the east, Shang diviners in China were scratching questions to their ancestors onto bone and shell — a script scholars count among the few invented without outside influence, with no link to the new alphabet.","kidsLink":"Far away in China, people scratched questions onto bones and shells. Their writing grew up on its own, with no link to the alphabet.","minAge":4},{"event":"phoenician-alphabet","year":-1050,"label":"The alphabet spreads","emoji":"🔤","link":"That desert script is the direct ancestor of the alphabet Phoenician traders spread from the Levantine coast: just 22 letters, all of them consonants, and easy to learn.","kidsLink":"That desert alphabet grew into the one Phoenician traders used. It had just 22 simple letters and was easy to learn.","minAge":4},{"event":"the-greek-alphabet-adds-vowels","year":-800,"label":"The Greek Alphabet Adds Vowels","emoji":"α","link":"The Greeks borrowed those Phoenician letters, which wrote consonants only, and used some of them for vowels — making the earliest known alphabet to write vowels and consonants alike.","kidsLink":"The Greeks borrowed those Phoenician letters, which had no vowels. They used some of the letters for vowel sounds instead.","minAge":4},{"event":"duenos-inscription-old-latin","year":-550,"label":"The Duenos Inscription, Early Latin","emoji":"📜","link":"In Italy the Etruscans took up the Greek alphabet used at Cumae and adapted it for their own language — and Rome, once ruled by the Etruscans, adapted the Etruscan letters for Latin, one borrowing on top of another.","kidsLink":"In Italy, the Etruscans took the Greek alphabet and changed it for their own language. Then Rome changed the Etruscan letters again to make the Latin alphabet we still use.","minAge":4},{"event":"zapotec-writing-danzantes","year":-350,"label":"The Zapotecs carve one of America's first scripts","emoji":"🪨","link":"Rome's alphabet had deep Mediterranean roots stretching back through Etruscan, Greek and Phoenician hands; on the other side of the world, with no contact with any of that lineage, the Zapotecs at Monte Albán were carving glyphs and dates into stone — writing invented in the Americas, with no link to the Old World.","kidsLink":"Rome's alphabet had roots going all the way back through Etruscan, Greek and Phoenician letters. Far away in the Americas, with no contact with any of that, the Zapotec people carved their own writing.","minAge":4},{"event":"edicts-of-ashoka","year":-250,"label":"Edicts Of Ashoka","emoji":"🪨","link":"Zapotec glyphs in Mesoamerica were one more script joining a growing list; in India, Emperor Ashoka had his edicts carved mostly in Brahmi, which would go on to father dozens of the scripts still used across South and Southeast Asia.","kidsLink":"The Zapotec script was one more new kind of writing. In India, Emperor Ashoka carved his rules using a script called Brahmi. Brahmi later grew into dozens of scripts still used in Asia today.","minAge":4},{"event":"cai-lun-invents-paper","year":105,"label":"Cai Lun Transforms Papermaking","emoji":"📄","link":"Writing still needed something cheap to go on: in China, bamboo and wooden slips were heavy and awkward, and silk was too expensive for wide use. The Han official Cai Lun is credited with refining papermaking from bark, hemp and old rags into cheap, smooth sheets.","kidsLink":"Writing still needed something cheap to go on. In China, Cai Lun is remembered for turning bark, hemp and old rags into cheap, smooth paper.","minAge":4},{"event":"the-codex-replaces-the-scroll","year":400,"label":"The Codex Replaces the Scroll","emoji":"📖","link":"Cai Lun's paper changed what to write on; in the Roman world, a separate change was under way in the shape of a book — pages bound at one edge, like the old wooden writing tablets, slowly displaced the rolled scroll, until by the 4th century the codex had become the shape reading would keep ever since.","kidsLink":"Cai Lun's paper changed what people wrote on. Meanwhile in the Roman world, people slowly stopped using long rolled-up scrolls and started binding pages together into books, just like the ones we use today.","minAge":4},{"event":"paper-reaches-baghdad","year":795,"label":"Paper reaches Baghdad","emoji":"📜","link":"Papermaking spread slowly west out of China along Central Asia's trade routes — a famous story credits Chinese prisoners taken at the Battle of Talas in 751, though one prisoner's own account names no papermakers — and by the 790s Abbasid Baghdad had one of the first paper mills in the Islamic world.","kidsLink":"Papermaking slowly traveled from China along trade routes all the way to Baghdad. There, one of the first paper mills in the Islamic world opened.","minAge":4},{"event":"diamond-sutra-print","year":868,"label":"The Diamond Sutra","emoji":"🖨️","link":"Back in China, where paper had been cheap for centuries, printers had learned to carve a whole page into a wooden block, ink it and press sheets from it — so in 868 a Buddhist scroll, later sealed in a cave at Dunhuang, was stamped from blocks rather than copied by hand.","kidsLink":"China had cheap paper for hundreds of years. Chinese printers carved whole pages onto wooden blocks and stamped them, instead of copying every page by hand.","minAge":4},{"event":"bi-sheng-movable-type","year":1040,"label":"Bi Sheng's Movable Type","emoji":"🀄","link":"A woodblock had to be carved afresh for every page; in the 1040s the craftsman Bi Sheng instead made single characters from baked clay, set them into pages and then sorted them away to reuse, letting one set of type print book after book.","kidsLink":"Carving a whole new block for every page took a long time. So a craftsman in China made tiny clay characters that could be arranged, then used again for page after page.","minAge":4},{"event":"jikji-metal-movable-type","year":1377,"label":"Jikji, Metal Movable Type","emoji":"⚙️","link":"Movable type did not stay in clay: Korean printers cast their characters in metal, and in 1377 monks used metal type to print Jikji, the oldest surviving book made this way.","kidsLink":"Later, Korean printers made their type out of metal instead of clay. They printed the oldest book we still have that was made with metal type.","minAge":4},{"event":"the-printing-press","year":1440,"label":"The Printing Press","emoji":"🖨️","link":"Korea had already printed with metal type decades earlier, and scholars still debate whether word of East Asian movable type reached Europe. In Mainz, Johannes Gutenberg combined metal movable type with a screw press, like those used to press grapes for wine, and paper, so books could be printed quickly.","kidsLink":"Korea had already printed with metal type years earlier. In Germany, Johannes Gutenberg built a press with metal letters that could print books fast. Experts still argue about whether he knew of Korea's idea.","minAge":4},{"event":"hangul-alphabet","year":1446,"label":"King Sejong invents Hangul","emoji":"🔤","link":"At about the same time as Gutenberg's work in Mainz, King Sejong in Korea tackled a different barrier to reading — ordinary Koreans had to master borrowed Chinese characters, so he designed Hangul from scratch, its basic consonant shapes modelled on the mouth and throat.","kidsLink":"At about the same time, in Korea, King Sejong invented a whole new alphabet: Hangul. Its main letters are shaped like the mouth and tongue making each sound.","minAge":4},{"event":"sequoyah-s-cherokee-syllabary","year":1821,"label":"Sequoyah's Cherokee Syllabary","emoji":"Ꮳ","link":"Sejong had shown a script could be designed on purpose for a people; nearly four centuries later and half a world away, the Cherokee silversmith Sequoyah did the same for his own language, single-handedly.","kidsLink":"King Sejong showed that a whole script could be made up on purpose. Long after, a Cherokee silversmith named Sequoyah did the same thing for his own people, all on his own.","minAge":4},{"event":"qwerty-typewriter-1873","year":1874,"label":"The QWERTY typewriter","emoji":"⌨️","link":"A press could mass-produce a finished book, but writing one still meant a pen. Then the Sholes and Glidden typewriter went on sale from Remington: a machine for typing your own words, and the source of the QWERTY keyboard layout we still use today.","kidsLink":"A printing press could print a finished book fast, but writing one still meant using a pen. Then a typewriter went on sale that let people type their own words. Its QWERTY keyboard is still used today.","minAge":4},{"event":"unicode-1-0-published","year":1991,"label":"Unicode Sets Out to Number Every Script","emoji":"🌐","link":"Computers once stored text in a patchwork of incompatible encodings, so words typed in one script could turn into garbled symbols on another machine. In 1991 the newly formed Unicode Consortium set out to give every character in the world's writing systems its own number.","kidsLink":"Before Unicode, text sent between computers often turned into odd symbols. Unicode set out to give every letter its own number. Then any computer could show the same text.","minAge":4},{"event":"iphone-2007","year":2007,"label":"The iPhone reinvents the phone","emoji":"📱","link":"Unicode had given every script a place in the digital world; in 2007 the iPhone dropped the physical keyboard for a glass touchscreen you tap and swipe, starting a shift of smartphones away from push-button keyboards — the pocket device on which so much of our writing now happens.","kidsLink":"The iPhone had no buttons for letters. You tapped a glass screen instead, and it fit in your pocket. Soon most phones worked the same way.","minAge":4}]},{"id":"the-story-of-money","title":"The story of money","emoji":"🪙","blurb":"Why does a piece of paper buy things? Because someone, somewhere, agreed to trust it — from clay tablets keeping accounts to coins, paper notes, banks, stock markets and phones that move money.","minAge":10,"kidsCut":true,"lens":"power","group":"making-and-trading","beats":[{"event":"cuneiform-is-born","year":-3300,"label":"Cuneiform Is Born","emoji":"📜","link":"Long before there were coins, there was a problem: how do you keep track of who has what? In Uruk, scribes drew signs into clay with a sharpened reed stylus to keep accounts, records that grew into cuneiform, the earliest known writing system.","kidsLink":"Long ago, people needed a way to keep track of things. In the city of Uruk, scribes drew signs into clay to keep count, and those signs grew into the oldest known writing.","minAge":4},{"event":"silver-shekel-as-money","year":-2150,"label":"Silver Shekel As Money","emoji":"⚖️","link":"Clay marks could keep accounts, but something still had to change hands. In Mesopotamia that something became silver, weighed out in shekels to pay for things long before coins existed; the word shekel is first recorded around 2150 BCE.","kidsLink":"Clay marks could keep count, but people still needed something to pay with. In Mesopotamia, they weighed out silver in units called shekels to pay for things.","minAge":4},{"event":"code-of-hammurabi","year":-1753,"label":"Code of Hammurabi","emoji":"⚖️","link":"Shekels already priced things: the Code of Hammurabi valued a year of unskilled work at about ten shekels. Money now had written law around it, set out in 282 laws carved on a basalt stele.","kidsLink":"Silver shekels were already used to pay for things. King Hammurabi had 282 laws carved into a tall stone, and they even put a price in shekels on a year of work.","minAge":4},{"event":"cowrie-shell-money","year":-1200,"label":"Cowrie Shell Money","emoji":"🐚","link":"Weighed silver was not the only answer to what to pay with. Far from Babylon, in Shang China, people used small cowrie shells, so trusted that the Chinese character for money still comes from the shell.","kidsLink":"Not everyone paid with silver. Far away in China, people used small cowrie shells as money. They trusted the shells so much that the Chinese sign for money still comes from them.","minAge":4},{"event":"zhou-spade-money","year":-700,"label":"Zhou cities cast spade-shaped money","emoji":"🪙","link":"Cowrie shells were natural objects used as money. In Zhou China, cities went further and cast metal money in the shape of spades; the thin blades show they were not meant for farming.","kidsLink":"Cowrie shells were money that nature made. In Zhou China, cities cast metal coins shaped like spades. Each was too thin to dig with.","minAge":4},{"event":"lydia-mints-first-coins","year":-650,"label":"Lydia Mints First Coins","emoji":"🪙","link":"Metal money was taking shape in more than one place. In the kingdom of Lydia, lumps of electrum, a natural gold-silver alloy, were stamped with a lion's head, the king's symbol, to make the world's first coins.","kidsLink":"Chinese cities cast metal money shaped like spades. In Lydia, people stamped lumps of gold-and-silver metal with a lion's head. These were the world's first coins.","minAge":4},{"event":"greek-silver-coinage-spreads","year":-550,"label":"Greek Silver Coinage Spreads","emoji":"🐢","link":"Lydia proved a stamp could vouch for a lump of metal. Greek city-states minted coins too: Aegina's silver 'turtles' travelled as far as Egypt and the Levant, and other cities minted to Aegina's weight, so a good coin could work as money far beyond the place that struck it.","kidsLink":"Greek cities made coins too. The Greek island of Aegina made silver coins stamped with a turtle, and they travelled as far as Egypt.","minAge":4},{"event":"indian-punch-marked-coins","year":-500,"label":"Indian Punch-Marked Coins","emoji":"🪙","link":"Stamped metal money was not only a Greek idea. From around the 6th century BCE the Mahajanapadas of the Indian subcontinent issued silver punch-marked coins stamped with symbols, and they stayed in circulation for centuries.","kidsLink":"Far from Greece, Indian kingdoms made silver coins stamped with symbols. They were some of the first coins in South Asia and were used for hundreds of years.","minAge":4},{"event":"roman-denarius","year":-211,"label":"Rome's denarius — money for an empire","emoji":"🪙","link":"Silver coins had by now been made for centuries in Greece and South Asia. Rome introduced its own around 211 BCE, during the Second Punic War, and the denarius became the backbone of Roman money for more than four centuries.","kidsLink":"Other lands already had silver coins. Around 211 BCE, Rome began making its own, the denarius. For more than 400 years it was the main coin people in Rome used.","minAge":4},{"event":"qin-unifies-chinese-coinage","year":-210,"label":"Qin Unifies Chinese Coinage","emoji":"🪙","link":"At about the same time, at the other end of Asia, the newly unified Qin empire replaced the many coins of its conquered states with one: a round coin with a square hole, a shape Chinese coins would keep for two thousand years.","kidsLink":"Rome had one standard coin. At about the same time, the Qin rulers who united China made everyone use just one coin too: round, with a square hole.","minAge":4},{"event":"the-islamic-gold-dinar","year":696,"label":"The Islamic Gold Dinar","emoji":"🟡","link":"Coinage could be remade by a ruler's decision. Caliph Abd al-Malik reformed it, issuing a new gold dinar bearing Arabic script; under the dynasties that followed, the dinar spread from Islamic Spain to Central Asia.","kidsLink":"Many years after Rome and Qin, Caliph Abd al-Malik made a new gold coin with Arabic writing on it. Later, people used it from Spain to Central Asia.","minAge":4},{"event":"hawala-sakk-credit","year":800,"label":"Letters of credit in the Islamic world","emoji":"📜","link":"If a coin's value lives in its metal, you still have to carry the metal. Traders in the Abbasid Caliphate let the metal stay put: a written letter of credit, the sakk, could move the money instead, cashed at a merchant's bank in another country.","kidsLink":"Gold coins had to be carried on long trips. Traders in the Abbasid world began using a written note called a sakk instead. They could cash it at a bank in another land.","minAge":4},{"event":"the-world-s-first-paper-money","year":1024,"label":"The world's first paper money","emoji":"💵","link":"A written order was a private promise between merchants. In Song China, the government itself took over the paper notes merchants had begun using in place of heavy iron coins and issued standard banknotes, the jiaozi, regarded as the first paper money in history.","kidsLink":"A note like the sakk was a promise between traders. In China, the Song government began issuing paper money called jiaozi, so people could spend paper instead of carrying heavy coins.","minAge":4},{"event":"the-bill-of-exchange","year":1200,"label":"The Bill Of Exchange","emoji":"📄","link":"China's paper money had a government behind it. Italian merchants found another way: building on notes long used by Middle Eastern traders, they took up the bill of exchange, a written order to pay money in another place, so they did not have to carry heavy, easily stolen coins.","kidsLink":"China's paper money had a government behind it. Italian traders used a different paper promise, first used by traders in the Middle East. It was a note that promised money in another city, called a bill of exchange.","minAge":4},{"event":"the-medici-bank","year":1397,"label":"The Medici Bank","emoji":"🏦","link":"A single bill of exchange is a promise between two merchants. The Medici turned that promise into an institution — a bank whose name was good enough to finance popes and princes across Europe.","kidsLink":"A bill of exchange was a promise between two traders. The Medici family in Florence turned that idea into a bank so trusted that popes and princes borrowed money from it.","minAge":4},{"event":"sher-shah-suri-mints-the-first-rupee","year":1540,"label":"Sher Shah Suri Mints The First Rupee","emoji":"🪙","link":"Banks were growing in Europe while coinage was still being standardised elsewhere. In South Asia, Sher Shah Suri standardized a silver rupiya of 178 grains, the direct ancestor of the rupees of India, Pakistan, Nepal and Sri Lanka today.","kidsLink":"Later, in South Asia, a ruler named Sher Shah Suri made a standard silver coin called the rupiya. The rupees used in several countries today come from it.","minAge":4},{"event":"silver-found-at-potosi","year":1545,"label":"Silver Found At Potosi","emoji":"⛏️","link":"Silver coins were standard money from Europe to South Asia. In the Andes, Spanish colonists began mining the mountain of Potosi, whose immense silver deposits would flood global markets and finance a worldwide bullion trade.","kidsLink":"Coins were made of silver in many lands. In the Andes, Spanish colonists began mining a mountain full of silver, which flowed into markets all around the world.","minAge":4},{"event":"voc-amsterdam-stock-exchange","year":1602,"label":"Shares for many and the Amsterdam stock market","emoji":"📈","link":"A worldwide bullion trade was growing. The Dutch East India Company, one of the first joint-stock companies, found a new way to gather money: it sold shares to a large pool of investors, including small merchants, soon traded in Amsterdam.","kidsLink":"Silver was flowing around the world. A Dutch trading company found a new way to get money: it sold little pieces of itself, called shares, to lots of people, who traded them in Amsterdam.","minAge":4},{"event":"the-bank-of-amsterdam","year":1609,"label":"The Bank Of Amsterdam","emoji":"🏦","link":"Seven years after the VOC was founded, Amsterdam got a bank. The Wisselbank, a pioneering public exchange bank, was founded to settle merchants' debts in reliable bank money, and it played a pivotal role in making Amsterdam a financial centre.","kidsLink":"Amsterdam already had a market for shares. Then the Bank of Amsterdam was founded to let merchants pay each other with reliable bank money.","minAge":4},{"event":"europe-s-first-banknotes","year":1661,"label":"Europe's First Banknotes","emoji":"💴","link":"Amsterdam's bank money helped merchants settle debts. Stockholms Banco tried turning that trust into something you could carry — notes redeemable for metal, Europe's first true banknotes, though issuing too many of them soon sank the bank.","kidsLink":"The Bank of Amsterdam helped merchants pay each other. A Swedish bank went further and printed paper notes people could carry and trade in for metal coins — Europe's first paper money.","minAge":4},{"event":"the-bank-of-england","year":1694,"label":"The Bank Of England","emoji":"🏛️","link":"Earlier banks lent to merchants and princes; England built one to lend to the state itself. The Bank of England was founded to fund the government's war, and grew into a model central bank that managed the currency and the national debt.","minAge":10},{"event":"britain-s-gold-standard","year":1821,"label":"Britain's Gold Standard","emoji":"🏅","link":"The Bank of England became a model central bank that managed the currency. Britain's banknotes could later be exchanged for gold again, completing its move to a gold standard with the pound a fixed weight of gold; from the 1870s gold became the basis of the international money system.","kidsLink":"The Swedish bank printed too much paper money, and it failed. Later, Britain let people swap its paper money for a fixed amount of gold. In time, gold became the basis of money between countries.","minAge":4},{"event":"germany-gold-mark-classical-gold-standard-1873","year":1873,"label":"Germany's gold mark starts the international gold standard","emoji":"🏅","link":"Britain had fixed its pound to a weight of gold. In 1873 the German Empire replaced its silver thaler and gulden with the gold mark, which prompted several other European countries to move to gold, and the gold standard became the basis of the international monetary system.","kidsLink":"Britain tied its money to gold. Then Germany swapped its silver coins for a new gold mark. Soon other countries chose gold too.","minAge":4},{"event":"the-federal-reserve","year":1913,"label":"The Federal Reserve","emoji":"🏦","link":"Gold stood behind the money, but a single bank could still fail and a panic could spread from bank to bank. After a series of such panics, the United States created the Federal Reserve, a central bank meant to stop bank runs by acting as the lender of last resort.","kidsLink":"Tying money to gold helped people trust it, but banks could still fail and panic could still spread. The United States created the Federal Reserve to act like a safety net, so banks wouldn't all collapse at once.","minAge":4},{"event":"britain-abandons-gold-standard-1931","year":1931,"label":"Britain Abandons the Gold Standard","emoji":"💷","link":"Even with central banks, the gold standard could break. Facing a run on the pound, Britain abandoned its promise to trade pounds for gold in 1931, other countries followed as the Great Depression deepened, and by the end of 1932 the system had collapsed.","kidsLink":"The Federal Reserve was built to stop banking panics. But in 1931 so many people rushed to trade British pounds for gold that Britain had to stop. As a huge crisis called the Great Depression got worse, other countries did the same.","minAge":4},{"event":"the-bretton-woods-system","year":1944,"label":"The Bretton Woods System","emoji":"🌐","link":"The old gold standard had collapsed. In 1944, 44 nations met in New Hampshire and built a new system: currencies pegged to a gold-backed dollar, with the IMF and World Bank to help run it.","kidsLink":"After the gold standard fell apart, 44 countries met to make new money rules. Their money would be tied to the US dollar. The dollar was tied to gold.","minAge":4},{"event":"the-dollar-leaves-gold","year":1971,"label":"The Dollar Leaves Gold","emoji":"💵","link":"Bretton Woods had pegged currencies to a gold-backed dollar. In 1971 President Nixon ended the direct international convertibility of the dollar into gold, effectively ending that system and helping usher in today's floating, fiat currencies.","kidsLink":"Bretton Woods tied the world's money to the US dollar, and the dollar to gold. In 1971, President Nixon stopped letting other countries trade their dollars for gold.","minAge":4},{"event":"m-pesa-turns-phones-into-kenyan-wallets","year":2007,"label":"M-Pesa Turns Phones into Kenyan Wallets","emoji":"📱","link":"Once money rested on trust rather than metal, it did not need coins, notes or even a bank branch. In Kenya, M-Pesa let people keep money on their phones and send it by text message; by 2010 it was the most successful mobile-money service in the developing world.","kidsLink":"Money is really just something people agree to trust. It does not need to be paper or coins at all. In Kenya, a new service called M-Pesa let people send money by phone, using simple text messages.","minAge":4},{"event":"bitcoin-genesis-block","year":2009,"label":"Bitcoin's First Block","emoji":"₿","link":"Every step so far asked you to trust someone — a king, a mint, a bank, a government, a phone company. Bitcoin's first block proposed trusting none of them: just a record of payments that a network of computers keeps, with no bank or government in charge.","kidsLink":"M-Pesa moved money by phone. Bitcoin went even further: no bank or government is in charge of it at all. Its record of payments is kept by a network of computers.","minAge":4}]},{"id":"how-we-learned-to-keep-time","title":"How we learned to keep time","emoji":"⏳","blurb":"A child asks a clock how it knows what time it is. The honest answer is a 5,000-year chase: leap after leap in precision was driven by something people urgently needed — a river's yearly flood, a temple's night rites, a ship's position, a railway timetable, a satellite fix.","minAge":7,"kidsCut":true,"lens":"science","group":"sky-space-and-time","beats":[{"event":"newgrange","year":-3100,"label":"Newgrange","emoji":"☀️","link":"Time becomes a story once people start marking it. Around 3100 BCE, Irish farmers built a tomb aligned so the winter-solstice sunrise floods its inner chamber, long before any clock existed. The chase starts with the sun.","kidsLink":"Long before clocks, people watched the sun. Irish farmers built a stone tomb that fills with sunlight at sunrise on the shortest day of the year.","minAge":7},{"event":"egyptian-calendar","year":-2500,"label":"The Egyptian 365-day calendar","emoji":"📅","link":"Newgrange marked one sunrise in the year. Egyptians tracked the whole year: a 365-day calendar of 12 months plus five extra days, probably set by the star Sirius, whose return to the dawn sky came around the start of the Nile flood.","kidsLink":"Newgrange marked just one day a year. Egyptians tracked the whole year with a 365-day calendar of 12 months. It was probably timed by a bright star that came back each year when the Nile flooded.","minAge":4},{"event":"egyptian-star-clocks","year":-2100,"label":"Egyptian Star Clocks","emoji":"🌌","link":"A calendar names the days, but not the hours of a night. Around 2100 BCE, star tables painted on Egyptian coffin lids used the rising of decan stars to tell time at night.","kidsLink":"A calendar told people which day it was, but not what time it was at night. Egyptians began watching special stars to tell the time after dark.","minAge":4},{"event":"telling-time-by-shadow","year":-1500,"label":"Telling Time By Shadow","emoji":"🌞","link":"Stars could mark the hours of the night; daylight needed hours of its own. Egyptians used shadow clocks and sundials, tracking the sun's moving shadow to split the day into hours.","kidsLink":"Stars helped mark the hours of the night. In the daytime, people watched a moving shadow instead, to split the sunny part of the day into hours too.","minAge":4},{"event":"karnak-water-clock-clepsydra","year":-1400,"label":"The water clock keeps time in the dark","emoji":"⏳","link":"A shadow is useless after dark. In the temple of Karnak, priests told the hours of the night with a bowl that let water out at a steady rate past marked lines, the oldest water clock ever found and a clock that worked without the sun.","kidsLink":"A shadow doesn't work after dark. So in an Egyptian temple, priests used a bowl that leaked water at a steady rate to mark the hours of the night.","minAge":4},{"event":"chinese-water-clocks-sixth-century-bce","year":-550,"label":"China uses water clocks for the stars","emoji":"🏮","link":"The water clock was not only an Egyptian idea. In China the oldest written reference to water clocks dates to the 6th century BC, where they were very important in the study of astronomy and astrology.","kidsLink":"Egypt was not the only place with water clocks. In China, people used them too, to help study the stars.","minAge":4},{"event":"ctesibius-and-the-water-clock","year":-270,"label":"Ctesibius perfects the water clock","emoji":"⏳","link":"Water clocks next improved in Alexandria, where Ctesibius made them better by regulating their flow. Water clocks then stayed the most accurate clocks for more than 1,800 years.","kidsLink":"In Alexandria, a man named Ctesibius made water clocks better. He found a better way to control how the water flowed out.","minAge":4},{"event":"astrolabe-latitude","year":-150,"label":"The astrolabe: a pocket model of the sky","emoji":"🔭","link":"Water clocks measured time with flowing water. Greek astronomers took another route and read it from the sky: with an astrolabe you measure the height of the Sun or a star, and get the time and your latitude.","kidsLink":"Water clocks counted time with dripping water. Greek astronomers built a tool called the astrolabe that worked out the time from how high the sun or a star sat in the sky.","minAge":4},{"event":"julian-calendar","year":-46,"label":"The Julian calendar","emoji":"📅","link":"Water clocks and astrolabes handled the hours; the calendar handled the years. In 46 BCE Julius Caesar reformed it to 365 and a quarter days with a leap year, the direct ancestor of the calendar we use today.","kidsLink":"Astrolabes helped with the hours of a day. Julius Caesar fixed the length of the year at 365 and a quarter days, and added a leap year.","minAge":4},{"event":"earliest-long-count-date","year":-36,"label":"Earliest Long Count Date","emoji":"📅","link":"Calendars were being built elsewhere too. At Chiapa de Corzo in Mesoamerica, Stela 2 bears one of the earliest known Long Count dates, 36 BCE, though the reading is not certain.","kidsLink":"People far away were keeping calendars too. A stone at Chiapa de Corzo, in Mesoamerica, has one of the earliest known dates in the Long Count calendar.","minAge":4},{"event":"yi-xing-and-the-mechanical-clock","year":725,"label":"Yi Xing's water-powered astronomical clock","emoji":"⚙️","link":"Centuries later, China took timekeeping in a new direction. The monk-astronomer Yi Xing and engineer Liang Lingzan built a water-driven sphere that struck bells and drums to mark the hours, using the earliest known escapement.","kidsLink":"Centuries later, in China, a monk and an engineer built a very different clock. It was powered by water and struck bells and drums to mark the hours.","minAge":4},{"event":"the-astrolabe-perfected","year":964,"label":"The astrolabe refined","emoji":"🧭","link":"While Chinese engineers built water-driven clockwork, Islamic astronomers took the older astrolabe in a different direction, refining it into an elegant 'computer' that could tell time, find latitude, locate the stars and fix the direction of Mecca.","kidsLink":"In China, engineers built a water-powered clock. Meanwhile, astronomers in the Islamic world improved the old Greek astrolabe. It could tell the time and locate the stars.","minAge":4},{"event":"a-water-powered-clock","year":1088,"label":"A Water-Powered Clock","emoji":"🕰️","link":"An astrolabe reads the time from the Sun or stars. In Song China, Su Song built a clock driven by water and an escapement that sounded the hours with bells and gongs: a working model in 1088, the full tower in Kaifeng by 1094.","kidsLink":"An astrolabe needs the sun or stars. In China, a scholar named Su Song built a tall clock powered by water that rang the hours by itself.","minAge":4},{"event":"mechanical-clock","year":1300,"label":"The mechanical clock","emoji":"🕰️","link":"Su Song's escapement was driven by water. Around 1300 in Europe, clocks driven by falling weights and controlled by an escapement appeared: the first true mechanical clocks, set in church towers to ring bells for prayer times and public events.","kidsLink":"Su Song's clock ran on water. Around 1300, European clocks ran on heavy falling weights instead. Church towers used them to ring bells, so people knew when to pray and meet.","minAge":4},{"event":"burgundy-clock-mainspring","year":1430,"label":"The oldest surviving spring-driven clock","emoji":"🔧","link":"A weight-driven clock needs a hanging weight, so it has to stay put. A coiled spring driving the gears let clocks become smaller and portable; the oldest surviving spring-driven clock, the Burgundy Clock, dates to about 1430.","kidsLink":"A clock run by a heavy weight had to stay in one place. Clockmakers began using a coiled metal spring instead, which let clocks get smaller and be carried around.","minAge":4},{"event":"jang-yeongsil-water-clock","year":1434,"label":"Korea's Self-Striking Water Clock","emoji":"🕰️","link":"While Europe moved to springs, Korea pushed the water clock further. Jang Yeong-sil built one for King Sejong in 1434 that struck a bell, gong and drum by itself, no human needed, and it kept the standard of time for Joseon Korea.","kidsLink":"Around the same time, in Korea, an engineer named Jang Yeong-sil built a water clock that struck bells, gongs and drums all by itself. No person had to call out the hour.","minAge":4},{"event":"gregorian-calendar-reform","year":1582,"label":"The calendar loses ten days","emoji":"📅","link":"Caesar's calendar slowly slipped. By 1582 the Julian calendar had drifted out of step with the seasons, so Pope Gregory XIII had October 4th followed straight by October 15th, with a cleverer leap-year rule. Most of the world still uses it.","kidsLink":"Caesar's calendar slowly slipped out of step with the seasons. In 1582 the Pope skipped ten days to fix it, and added a better leap-year rule.","minAge":4},{"event":"the-pendulum-clock","year":1656,"label":"The Pendulum Clock","emoji":"⏰","link":"The next big gain in accuracy came from a swinging pendulum. In 1656 Christiaan Huygens built a clock kept steady by one, improving clocks from losing about 15 minutes a day to about 15 seconds.","kidsLink":"The next big step came in 1656. Christiaan Huygens built a clock kept steady by a swinging pendulum, and clocks went from being wrong by minutes to seconds a day.","minAge":4},{"event":"balance-spring-1675","year":1675,"label":"The balance spring tames the watch","emoji":"🌀","link":"A pendulum needs a clock that stays still. For watches, the fix in the mid-1670s was a coiled hairspring on the balance wheel, taking watches from perhaps several hours a day out to about ten minutes: useful timekeepers at last.","kidsLink":"A swinging pendulum needs a clock that stays still, so it was no help to pocket watches. A tiny coiled spring called a hairspring made watches much more accurate.","minAge":4},{"event":"harrison-marine-chronometer-longitude","year":1761,"label":"Harrison's sea clock solves longitude","emoji":"⏱️","link":"Watches were now useful on land, but finding longitude at sea needed accurate time on a rolling ship, and Parliament had offered up to 20,000 pounds to solve it. John Harrison's H4 was only 5 seconds slow on its Atlantic trial to Jamaica.","kidsLink":"Watches were more accurate now, but ships needed something tougher. John Harrison built a clock that kept time even on a rocking ship, so sailors could find how far east or west they were.","minAge":4},{"event":"railway-time-britain-gmt","year":1847,"label":"Railway time: Britain shares one clock","emoji":"🚂","link":"Accurate clocks were not enough if every town kept its own time, up to twenty minutes apart. In 1847 the Railway Clearing House called for Greenwich time at every station, and from 1 December the London and North Western and Caledonian railways switched.","kidsLink":"Ships could now keep good time at sea. On land, British trains had a problem: every town kept its own time. In 1847 the railways began using one shared clock time.","minAge":4},{"event":"standard-time-zones-1883","year":1883,"label":"Railways bring standard time to North America","emoji":"🕰️","link":"North America had the same muddle on a bigger scale. On 18 November 1883 the railways of the United States and Canada scrapped a jumble of local times and reset their clocks to a few standard time zones, on a telegraph signal sent at noon.","kidsLink":"North American trains had the same problem as British ones, across a whole continent. In 1883 the railways swapped many local times for a few time zones.","minAge":4},{"event":"international-meridian-conference-1884","year":1884,"label":"The world picks one meridian","emoji":"🌐","link":"Railways had pulled whole countries onto shared clocks; in 1884 the question went worldwide. Delegates from 26 nations picked the line through Greenwich as the zero meridian, the reference point for both longitude and a shared universal day.","kidsLink":"Railways had put whole countries on shared clocks. In 1884, countries around the world met and agreed that Greenwich, England would be the starting point for measuring time and place.","minAge":4},{"event":"first-quartz-clock-bell-labs","year":1927,"label":"The first quartz clock ticks","emoji":"💎","link":"With the world agreed on where time was measured from, the next leap was measuring it better. In 1927 at Bell Labs, Warren Marrison and Joseph Horton built the first clock run by a vibrating quartz crystal, which kept time more accurately than a pendulum clock.","kidsLink":"The world had agreed where to measure time from. Next came a better way to measure it: in 1927, two scientists built the first clock powered by a buzzing quartz crystal.","minAge":4},{"event":"caesium-atomic-clock-npl-1955","year":1955,"label":"The first practical caesium atomic clock","emoji":"⚛️","link":"Mechanical and quartz clocks lose accuracy as the temperature changes. In 1955 Louis Essen and Jack Parry at Britain's National Physical Laboratory built a clock that counted the vibrations of caesium atoms instead, letting time be kept far more accurately.","kidsLink":"Quartz clocks kept great time, but they could still drift a little. In 1955, two scientists built a new clock that counted the shaking of tiny caesium atoms instead.","minAge":4},{"event":"second-redefined-1967","year":1967,"label":"The second becomes an atom's beat","emoji":"⏱️","link":"Earth's rotation varies and is slowing slightly, while an atom's vibration is one of the most stable things in nature. So in 1967 the second stopped being a fraction of Earth's spin or orbit and became exactly 9,192,631,770 vibrations of a caesium-133 atom.","kidsLink":"The atomic clock showed atoms keep better time than the spinning Earth. So in 1967, scientists redefined the second itself as a fixed number of atom vibrations.","minAge":4},{"event":"seiko-launches-the-first-quartz-wristwatch","year":1969,"label":"Seiko Launches The First Quartz Wristwatch","emoji":"⌚","link":"Meanwhile the quartz idea from Bell Labs in 1927 shrank to wrist size. Seiko unveiled the Astron in Tokyo on 25 December 1969, the first quartz wristwatch on sale, far more accurate than mechanical watches.","kidsLink":"Meanwhile, the quartz crystal idea from 1927 got small enough to wear. A Japanese company, Seiko, made the first quartz wristwatch you could buy.","minAge":4},{"event":"utc-leap-second-1972","year":1972,"label":"UTC adds the leap second","emoji":"🕛","link":"Atomic clocks now kept a steadier beat than the Earth's own spin, which is slightly uneven. In 1972, Coordinated Universal Time fixed the mismatch with the leap second: an extra second added now and then so UTC's seconds keep the atom's exact beat while its time of day still tracks the turning Earth.","kidsLink":"Clocks had become more accurate than the spinning Earth, which changes speed very slightly. So in 1972, official time got a fix called the leap second, added now and then to keep clocks and Earth in step.","minAge":4},{"event":"gps-fully-operational","year":1995,"label":"GPS becomes fully operational","emoji":"📍","link":"UTC kept civil clocks within a second of the turning Earth. GPS went further: its satellites carry very stable atomic clocks, synchronized with each other and with reference clocks on the ground, letting a receiver almost anywhere work out where it is.","kidsLink":"UTC kept official clocks matched to Earth's spin. GPS put very steady atomic clocks on satellites, so a device almost anywhere can work out where it is.","minAge":4},{"event":"leap-second-abolished-vote-2022","year":2022,"label":"The world votes to drop the leap second","emoji":"🗳️","link":"GPS keeps its own time, untouched by leap seconds, while each leap second added to UTC could trip up software: in 2012 one caused problems for sites and an airline. In 2022 the world's standards body voted to stop adding them by 2035.","kidsLink":"GPS keeps its own atomic time with no leap seconds. Leap seconds sometimes caused computer problems, and in 2022 the world voted to stop adding them by 2035.","minAge":4}]},{"id":"how-we-fed-everyone","title":"How we learned to feed everyone","emoji":"🌾","blurb":"From a flint sickle cutting wild grain to a world of eight billion mostly fed — the story of how humans learned to grow, move and keep enough food, across the world, and what each leap forward cost.","minAge":10,"kidsCut":true,"lens":"science","group":"food-and-health","beats":[{"event":"natufian-sickle-blades","year":-13000,"label":"Stone Sickles for Wild Grain","emoji":"🔪","link":"A child asks where all the food comes from, and the answer starts here: before anyone planted a single seed on purpose, people already knew exactly which wild grasses were worth cutting, and built a tool — flint blades set into a handle — just for that job.","kidsLink":"This is where the story of farming begins. Long before anyone grew food on purpose, people already knew which wild plants were good to eat, and made a special tool to cut them.","minAge":4},{"event":"fertile-crescent-first-farming","year":-9500,"label":"The first farmers sow wheat","emoji":"🌾","link":"After thousands of years of harvesting wild grain, an obvious question arose: why not grow it exactly where you want it? In the Fertile Crescent, wheat and barley became some of the very first crops people planted rather than simply found.","kidsLink":"People had been cutting wild grains for a long time. Then they asked a big question: why not plant them exactly where we want them to grow? That is how farming began.","minAge":4},{"event":"pig-domestication","year":-9400,"label":"Pigs join the farm","emoji":"🐖","link":"Planting grain solved one problem, but people also wanted meat. Wild boar were tamed into pigs, first in the Near East around the Tigris Basin more than 11,400 years ago, and separately in China about 8,000 years ago.","kidsLink":"Growing grain was a great start, but people wanted meat too. Wild boars were tamed into pigs, first in the Middle East, and later, on their own, in China.","minAge":4},{"event":"sheep-and-goats-tamed","year":-9000,"label":"Sheep And Goats Tamed","emoji":"🐐","link":"Pigs gave early farmers meat. In the hills of the Fertile Crescent, farmers also began herding wild sheep and goats instead of only hunting them, gaining a steady supply of meat, milk and skins.","kidsLink":"Pigs gave farmers meat. People also began herding wild sheep and goats instead of just hunting them, for meat, milk and skins.","minAge":4},{"event":"cattle-domestication","year":-8500,"label":"Wild cattle are tamed","emoji":"🐂","link":"Sheep and goats gave meat, milk and skins; the wild aurochs added something new. Tamed into cattle, it also gave leather and muscle to pull loads, which would matter once farmers had something heavy to drag.","kidsLink":"Sheep and goats gave people milk and meat. Wild cattle were tamed too, and they gave something extra: strong muscles to pull heavy loads.","minAge":4},{"event":"rice-domestication-china","year":-7000,"label":"Rice farming begins in China","emoji":"🍚","link":"With sheep, goats, pigs and cattle tamed, people were learning to grow plants as well. Along the Yangtze River in China, communities domesticated wild rice, a crop that is today the staple food of over half the world's people.","kidsLink":"People had already tamed animals like cattle. Along the Yangtze River in China, people also began growing wild rice.","minAge":4},{"event":"new-guinea-agriculture","year":-7000,"label":"Farming invented in New Guinea","emoji":"🍌","link":"Rice wasn't the only crop being tamed from scratch around this time. In the swampy highlands of New Guinea, an entirely separate group of people drained the wetland to farm taro, and later bananas and yams — one of the world's few places where farming began independently.","kidsLink":"Rice was not the only plant people were learning to farm. In the swampy hills of New Guinea, other people dug ditches to grow taro, and later bananas and yams, and they figured it out all on their own.","minAge":4},{"event":"balsas-teosinte-to-maize","year":-7000,"label":"Teosinte becomes maize in the Balsas Valley","emoji":"🌽","link":"New Guinea's farmers built their own crops out of local wild plants, and across the Pacific in Mexico's Balsas Valley, people were doing the same with a different one: slowly reshaping a scraggly wild grass called teosinte, generation after generation, until it became maize.","kidsLink":"Just like people in New Guinea grew their own crops from wild plants, farmers in Mexico did too. They slowly changed a wild grass called teosinte until it became corn.","minAge":4},{"event":"peiligang-culture-millet","year":-6500,"label":"Peiligang — millet, pigs and stone sickles","emoji":"🌾","link":"Maize was Mexico's answer to feeding people from a wild grass; in the Yi-Luo river basin of central China, farmers of the Peiligang culture grew their own local grass, millet, raised pigs, and harvested their grain with stone sickles.","kidsLink":"In Mexico, farmers turned a wild grass into corn. In China, another group of farmers grew a different grass called millet, raised pigs, and cut their grain with stone sickles.","minAge":4},{"event":"potato-llama-andes","year":-6000,"label":"Potatoes and llamas in the Andes","emoji":"🥔","link":"Each farming homeland tamed what grew there. High in the Andes, around Lake Titicaca, people domesticated a mountain tuber, the potato, and in the millennia that followed tamed the llama and alpaca for wool and for carrying loads — a farming tradition all their own.","kidsLink":"Farmers in China grew millet, a plant that suited their land. High in the Andes mountains, people grew a food that suited theirs, the potato, and later tamed llamas and alpacas too.","minAge":4},{"event":"irrigation-mesopotamia","year":-6000,"label":"Some of the first irrigation canals","emoji":"💧","link":"Every early farming centre worked with the land it had. On the edge of the dry Mesopotamian plain the limit was water, so farmers at Choga Mami dug channels to carry river water out to their fields.","kidsLink":"People in the Andes grew food that suited the high mountains. In Mesopotamia, the problem was different: the fields were dry. So farmers dug channels to bring river water to them.","minAge":4},{"event":"plough-invented","year":-4000,"label":"The ox-drawn plough","emoji":"🐂","link":"Once water could reach a field, the next limit was how much ground one family could break open by hand. Yoking an ox to a simple plough let a single farmer turn far more soil than any hoe.","kidsLink":"Once water could reach the fields, there was a new problem: how much ground could one family dig by hand? Farmers hitched an ox to a simple plough, and one person could dig up much more land.","minAge":4},{"event":"pearl-millet-domesticated-sahel","year":-2500,"label":"Pearl millet is tamed in the Sahel","emoji":"🌾","link":"Not every farmer had a river to divert or oxen to yoke. In the Sahel of West Africa, farmers domesticated pearl millet, a tough grain that copes with drought and heat — proof that canals and ploughs were never the only road to a reliable harvest.","kidsLink":"Not every farmer had a river or an ox and plough. In the Sahel of West Africa, farmers tamed a tough grain called pearl millet that could grow in hot, dry places.","minAge":4},{"event":"salt-poisons-sumer-s-irrigated-fields","year":-1700,"label":"Salt Poisons Sumer's Irrigated Fields","emoji":"🧂","link":"Pearl millet could cope with drought; in Sumer, water itself became the trouble. Centuries of irrigating without proper drainage built up salt in the soil, cutting harvests so badly that farmers swapped their wheat for hardier barley.","kidsLink":"Farmers in Africa had learned to grow food in dry places. But in Sumer, years of watering fields the wrong way let salt build up in the soil, and harvests shrank because of it.","minAge":7},{"event":"han-dynasty-iron-plough-row-farming","year":-100,"label":"Han China's iron plough and seed drill","emoji":"🌾","link":"Sumer's salted fields showed that farming could go wrong, but elsewhere it kept improving. Much later, in Han dynasty China, farmers worked with a heavy iron plough pulled by two oxen, paired with an iron seed drill that planted grain in careful rows rather than scattering it by hand.","kidsLink":"Farming in Sumer had gone wrong because of bad watering. Much later in China, farmers used better tools: a strong iron plough and an iron tool that planted seeds in neat rows.","minAge":4},{"event":"arab-agricultural-revolution-spreads-crops","year":900,"label":"Crops spread across the Islamic world","emoji":"🍊","link":"Han China had shown what better tools could do for a field already planted with familiar crops. Centuries later, by the historian Andrew Watson's account, trade across the Islamic world tackled a different limit — which crops were available at all — carrying sorghum, citrus, rice, cotton and sugar cane into new lands.","kidsLink":"In China, farmers built better tools to grow the crops they already had. Later, traders across the Muslim world carried whole new crops, like rice, sugar cane and citrus fruit, to places that had never grown them.","minAge":4},{"event":"chinampas-floating-gardens-1350","year":1350,"label":"The Aztecs farm the lake with floating gardens","emoji":"🌾","link":"Where the Arab world's revolution was about moving crops across huge distances, the Aztecs stayed put and farmed the lake itself: chinampas, fertile mud-and-reed plots staked into the shallow lake around Tenochtitlan, worked on a large scale and yielding up to seven harvests a year.","kidsLink":"Traders in the Muslim world carried new crops across huge distances. Far away, the Aztecs farmed right in a lake, on garden plots of mud and reeds called chinampas.","minAge":4},{"event":"columbian-exchange","year":1492,"label":"The Columbian Exchange begins","emoji":"🥔","link":"The Americas grew crops found nowhere else, and after 1492 the wider world finally met them. Potatoes, maize and tomatoes crossed the Atlantic eastward while wheat and horses went west, in an exchange of crops and animals that reshaped diets worldwide.","kidsLink":"Farmers in the Americas grew crops nobody outside the Americas had seen. After 1492, ships began carrying crops like potatoes and maize across the ocean. Wheat and horses travelled the other way.","minAge":4},{"event":"tull-s-seed-drill","year":1701,"label":"Tull's Seed Drill","emoji":"🌱","link":"The Columbian Exchange changed which crops people grew; in England, Jethro Tull changed how seed went into the ground — his horse-drawn drill sowed it economically in neat rows at the right depth instead of scattering it by hand.","kidsLink":"Ships had carried new crops around the world. In England, Jethro Tull found a better way to plant seeds: a machine that put them in neat rows instead of scattering them by hand.","minAge":4},{"event":"townshend-norfolk-rotation-1730","year":1730,"label":"Turnips and clover feed the farming revolution","emoji":"🌱","link":"Tull's drill improved how seed was sown; the Norfolk rotation improved what the land did between harvests. Wheat, turnips, barley and clover replaced leaving fields fallow, restoring the soil and growing winter fodder for animals.","kidsLink":"Tull's machine planted seeds better. Farmers also found a smart way to rest the soil: they grew a different crop each year, like turnips and clover, instead of leaving a field empty.","minAge":4},{"event":"the-great-bengal-famine-kills-millions","year":1770,"label":"The Great Bengal Famine","emoji":"🌾","link":"Better farming never guaranteed that people would get to eat. As Britain's agricultural revolution got under way, Bengal's crops failed in 1768 and 1769, and an East India Company that gave little relief and did not cut taxes made the famine worse: famine is shaped by decisions, not just weather.","minAge":10},{"event":"appert-canning","year":1810,"label":"Canned food is invented","emoji":"🥫","link":"Growing food was only half the problem; keeping it from spoiling was the other. In France, Nicolas Appert found that sealing food in glass jars and boiling them kept it from spoiling, and in 1810 the government paid him to make his method public.","kidsLink":"Farmers in England had learned to keep their soil healthy and to grow food for their animals all year round. Then a Frenchman named Nicolas Appert found a way to keep food from going bad, by sealing it in jars and boiling them.","minAge":4},{"event":"mccormick-mechanical-reaper-1831","year":1831,"label":"McCormick's reaper mechanizes the harvest","emoji":"🌾","link":"Appert had solved how to keep food from spoiling; the next problem was how much work a harvest took. In 1831, 22-year-old Cyrus McCormick demonstrated a horse-drawn mechanical reaper, and reapers like his cut the human labour of harvesting grain.","kidsLink":"Nicolas Appert found a way to keep food from going bad. A young man named Cyrus McCormick solved a different problem: he built a horse-drawn machine that let farmers harvest grain with fewer workers.","minAge":4},{"event":"irish-famine-1845","year":1845,"label":"The Great Irish Famine","emoji":"🥔","link":"Harvesting machines still couldn't protect people who depended on a single crop. Bengal had shown that a famine can be shaped by decisions, not only by weather; Ireland's began with a different risk — when blight struck the potato, famine killed about a million people and drove over a million more to emigrate.","minAge":10},{"event":"ss-dunedin-frozen-meat-1882","year":1882,"label":"New Zealand's first frozen-meat voyage","emoji":"❄️","link":"Famine showed what happens when food is scarce in one place; refrigeration let surplus in one place reach another. The Dunedin carried frozen New Zealand mutton to London, still sound after 98 days, proving meat could be shipped frozen across the world.","kidsLink":"Cyrus McCormick's machine helped harvest grain. Then a ship called the Dunedin carried frozen meat all the way from New Zealand to London, and it was still good to eat.","minAge":4},{"event":"haber-synthesizes-ammonia-from-air","year":1909,"label":"Haber Synthesizes Ammonia From Air","emoji":"🌾","link":"Ships could now move food worldwide; the next leap was in the soil. Fritz Haber found a way to make ammonia from the nitrogen in the air, now fertilizing much of the world's food; nearly 50% of the nitrogen in human tissues comes from it, at the cost of heavy energy use and nitrate pollution.","kidsLink":"A ship had carried frozen meat across the world. Many years later, scientist Fritz Haber found a way to make plant food called fertilizer using a gas from the air, helping farms grow much more food.","minAge":4},{"event":"fordson-tractor-replaces-draft-animals","year":1917,"label":"The Fordson tractor takes over the farm","emoji":"🚜","link":"Haber's fertilizer raised how much a field could grow; the next bottleneck was how fast a farm could work that field. From 1917, Henry Ford's mass-produced Fordson tractor began replacing horses on American farms, and during the Great Depression the share of US farms with a tractor rose to two in five.","kidsLink":"Fritz Haber's discovery helped fields grow much more food. Soon after, Henry Ford's new tractor, called the Fordson, began replacing horses on farms.","minAge":4},{"event":"holodomor-famine-1933","year":1933,"label":"Famine Engulfs Soviet Ukraine","emoji":"🌾","link":"Tractors and fertilizer made the best-off farms more productive than ever, but that offered no protection when a government turned against its own farmers. Through 1932-33 the Soviet state seized grain harvests across Ukraine and punished resisting peasants, and millions starved in what is remembered as the Holodomor.","minAge":10},{"event":"china-great-famine-1959","year":1959,"label":"The Great Chinese Famine","emoji":"🌾","link":"A quarter century after the Holodomor, government policy again ended in famine, this time in China. Caused largely by the policies of the Great Leap Forward, famine spread across China from 1959 to 1961; the toll is still intensely debated, with estimates from about 15 million to 46 million deaths.","minAge":10},{"event":"green-revolution-wheat","year":1966,"label":"Green Revolution Wheat","emoji":"🌾","link":"Policy could still starve millions, but plant breeding offered another kind of insurance. Tall wheat tends to collapse under the extra grain that nitrogen fertilizer brings, so Norman Borlaug bred shorter, stronger stalks, and in India and Pakistan wheat yields nearly doubled between 1965 and 1970.","kidsLink":"Tractors helped farmers work faster. Later, a scientist named Norman Borlaug bred a new kind of wheat that grew much more grain in the same field, and farmers in India and Pakistan grew almost twice as much.","minAge":7},{"event":"ir8-miracle-rice-1966","year":1966,"label":"IR8 'miracle rice' reaches farmers","emoji":"🍚","link":"Borlaug had made wheat shorter and stronger; rice got its own semi-dwarf. At the International Rice Research Institute, breeders crossed a dwarf variety from Taiwan with a high-yielding Indonesian rice, and IR8 lifted yields from 1 or 2 tons per hectare to 4 or 5.","kidsLink":"A scientist had bred better wheat. At about the same time, other scientists bred a shorter kind of rice called IR8, and farmers could grow much more food from each field.","minAge":4},{"event":"first-gm-crops-planted-1996","year":1996,"label":"GM crops spread to farms worldwide","emoji":"🌽","link":"Borlaug's wheat and IR8 rice were both improved by traditional breeding, cross by cross. By the 1990s scientists had a new tool: adding genes directly to a crop, for example to help it resist insects, and by 1996 farmers were growing genetically modified crops on 1.7 million hectares worldwide.","kidsLink":"Scientists had bred better rice by choosing which plants to grow next. Later, they found a new way to change plants: adding new genes directly, for example to help crops fight off insects.","minAge":4},{"event":"world-population-passes-eight-billion-2022","year":2022,"label":"World population passes eight billion","emoji":"🌍","link":"GM crops were the newest tool in a 15,000-year chain of them — sickles, ploughs, fertilizer, bred wheat — each helping the planet feed more people. On 15 November 2022 the UN marked the population passing eight billion, yet that same year about 735 million people still faced hunger.","kidsLink":"Genetically modified crops were the newest tool for growing more food. In 2022, the world reached eight billion people, but even then hundreds of millions of people still did not have enough to eat.","minAge":7}]},{"id":"the-story-of-cloth","title":"The story of cloth","emoji":"🧵","blurb":"Where do clothes come from? Follow cloth from a 50,000-year-old bone needle to a fast-fashion rack, through looms, empires, slavery and synthetic thread.","minAge":10,"kidsCut":true,"lens":"science","group":"making-and-trading","beats":[{"event":"denisova-eyed-needle","year":-48000,"label":"One of the oldest known needles","emoji":"🪡","link":"The story of cloth starts not with fabric but with sewing: a slender bird-bone needle from Denisova Cave, about 50,000 years old, is one of the oldest sewing needles known.","kidsLink":"This is where the story of cloth begins: a needle used to sew clothes about 50,000 years ago.","minAge":4},{"event":"dzudzuana-dyed-flax","year":-28000,"label":"Oldest known dyed flax fibres","emoji":"🧵","link":"A needle is only useful with thread to feed it. Long after the Denisova needle, people in a cave in Georgia spun and knotted wild flax fibres and dyed some of them — the oldest dyed flax fibres known, and the earliest evidence of people using wild flax to make textiles.","kidsLink":"A needle needs thread to work. Long after that needle, people in a cave learned to twist and dye plant fibers into string — the oldest dyed flax threads ever found.","minAge":4},{"event":"guitarrero-cave-first-beans","year":-8000,"label":"Guitarrero Cave — early beans and South America's oldest cloth","emoji":"🫘","link":"Twisting plant fibres into thread was not a single invention. Some twenty thousand years later and half a world away, people in a Peruvian cave wove their own plant fibres — South America's oldest known — and the cave also kept beans, chili peppers and other early cultivated plants.","kidsLink":"People didn't invent thread just once. Much later, and far away in Peru, people also wove plant fibers. Their cave also kept beans, chili peppers and other early farm plants.","minAge":4},{"event":"flax-domesticated-fertile-crescent","year":-7000,"label":"Flax is tamed — for oil and linen","emoji":"🌱","link":"Fibre could be gathered from wild plants; in the Fertile Crescent, farmers took a further step and domesticated the plant itself — breeding flax as a crop grown for its fibre and oil, not just picked from the wild.","kidsLink":"People could gather wild plants for fiber. In the Fertile Crescent, farmers went further: they grew a plant, flax, just to make thread and oil from it.","minAge":4},{"event":"nahal-hemar-ritual-cave","year":-7000,"label":"Nahal Hemar — a Stone Age ritual store","emoji":"💀","link":"In the same millennium, a dry cave near the Dead Sea kept rope baskets, nets and flax fabrics from what may have been an ancestor cult. Its looped flax threads make it the earliest known place of crochet-like looping.","kidsLink":"Around the same time, a dry desert cave near the Dead Sea kept baskets and cloth that people had made long ago.","minAge":7},{"event":"woven-cloth-loom","year":-6500,"label":"Early woven cloth at Çatalhöyük","emoji":"🧵","link":"Flax was being worked into fabric in the Levant; at Çatalhöyük in Turkey, a town that flourished around 7000 BC, people left some of the earliest-known weaving in the Near East. The fibre, long taken for flax, turns out to be oak bast, the inner bark of oak trees.","kidsLink":"Cloth was being made in Turkey too. In an old town there, people wove threads over and under each other. Scientists found the threads were made from the inner bark of oak trees, not flax.","minAge":4},{"event":"jiahu-silk","year":-6500,"label":"World's oldest known silk, in China","emoji":"🐛","link":"At almost the same time, on the other side of Asia, a different fibre was in use. Chemical traces of silk in 8,500-year-old tombs at Jiahu, plus weaving tools and bone needles, are the earliest known evidence of silk, which people there may have woven or sewn into cloth.","kidsLink":"At about the same time, in China, people were using a different fiber: silk. Scientists found signs of it in very old tombs, along with weaving tools and needles.","minAge":7},{"event":"mehrgarh-earliest-cotton","year":-6000,"label":"Some of the oldest cotton threads — at Mehrgarh","emoji":"🧵","link":"Silk was China's fibre; in the Indus region, a different one was in use. Mineralised cotton threads inside a string of copper beads at Mehrgarh are among the earliest known evidence of people using cotton fibre.","kidsLink":"China had silk. Far away near the Indus River, people used a different fiber called cotton. Tiny threads found inside old copper beads are among the earliest signs of people using cotton.","minAge":4},{"event":"cotton-domesticated-peru","year":-4200,"label":"Cotton is domesticated on Peru's coast","emoji":"🧵","link":"Cotton threads were in use near the Indus; half a world away, people on Peru's coast were growing a cotton of their own. They made native cotton into fishing nets and cloth, and it became the backbone of later coastal cultures such as the Moche and Nazca.","kidsLink":"People near the Indus River used cotton. Far away on Peru's coast, people grew their own native cotton too, and made it into fishing nets and cloth.","minAge":4},{"event":"indigo-dye","year":-4200,"label":"The oldest blue: indigo dye in Peru","emoji":"🔵","link":"Peru's coastal people grew cotton for nets and cloth, and at Huaca Prieta they also coloured it: cotton cloth dyed with indigo at least 6,200 years ago is the oldest indigo-dyed fabric known — the same blue that colors jeans today.","kidsLink":"People in Peru grew cotton for nets and cloth. They also dyed their cotton cloth blue with indigo — the oldest blue cloth ever found.","minAge":4},{"event":"first-woolly-sheep","year":-4000,"label":"The first woolly sheep","emoji":"🐑","link":"Peru had cotton, dyed blue with indigo; herders in the Near East took a different path to fibre entirely, breeding sheep with longer fleece that could be spun — turning a living animal into a source of cloth.","kidsLink":"In Peru, people grew and dyed cotton. In the Near East, people did something different: they bred sheep with soft wool that could be spun into thread.","minAge":4},{"event":"silk-from-silkworms","year":-3600,"label":"Silk From Silkworms","emoji":"🐛","link":"Near Eastern herders bred sheep for wool; in China, people turned to a different creature, the silkworm, learning to unwind its fine threads and weave them into silk, a secret they guarded for centuries.","kidsLink":"In the Near East, people bred sheep for wool. In China, people used a different animal, the silkworm. They learned to unwind its cocoons into silk thread and kept the secret for a very long time.","minAge":4},{"event":"harappan-cotton-earliest-cloth","year":-2600,"label":"The Indus weaves cotton cloth","emoji":"🧵","link":"While China guarded its silk, the Indus Valley, where cotton threads had been used at Mehrgarh thousands of years before, had become home to some of cotton's early growers, spinning and weaving it into cloth.","kidsLink":"While China kept silk a secret, people back near the Indus River grew cotton and wove it into cloth. They were among the early cotton weavers of the world.","minAge":4},{"event":"tyrian-purple-from-murex-shells","year":-1500,"label":"Tyrian purple — royal dye from crushed sea snails","emoji":"🐚","link":"Cotton cloth was now made from the Indus to Peru; what set some cloth apart was color. Phoenician dyers crushed thousands of murex sea snails for a single gram of dye so costly it was worth its weight in silver — 'royal purple.'","kidsLink":"By now people made cloth in many places. What made some cloth special was color: Phoenician dyers crushed thousands of sea snails to make a tiny bit of purple dye that was worth its weight in silver.","minAge":4},{"event":"paracas-embroidered-textiles","year":-300,"label":"The Paracas weave dazzling embroidered cloth","emoji":"🧵","link":"Purple dye made cloth a mark of kings in the Mediterranean; on Peru's dry south coast, fine cloth went with the dead. The Paracas wrapped their dead in many layers of richly embroidered textiles, which kept their colours for more than two thousand years in the dry desert ground.","kidsLink":"Purple dye made cloth special in one place. In Peru, the Paracas people wrapped their dead in beautifully stitched cloth. The dry desert kept it safe for thousands of years.","minAge":7},{"event":"silk-road","year":-130,"label":"Silk Road opens","emoji":"🐫","link":"While Andean weavers made textiles for their own dead, on the other side of the world Han China opened trade routes west across Central Asia, and for centuries the Silk Road carried silk, spices and technologies between East and West.","kidsLink":"In Peru, people made cloth for their dead. On the other side of the world, China opened long trade routes. For hundreds of years they carried silk, spices and ideas between East and West.","minAge":4},{"event":"the-spinning-wheel","year":1030,"label":"The Spinning Wheel","emoji":"🧵","link":"Thread was still spun by hand, one twist at a time, until a faster tool appeared: by 1030 the spinning wheel was known in the Middle East (some historians think India had it even earlier), making thread more than ten times as productively as spinning by hand.","kidsLink":"For a long time, people spun thread by hand. By about 1030, people in the Middle East were using a new tool, the spinning wheel. It made thread more than ten times faster.","minAge":4},{"event":"calico-acts-ban-indian-cotton-1721","year":1721,"label":"Britain's Calico Acts ban Indian cotton","emoji":"🚫","link":"Even with spinning wheels, England's own cloth lost buyers to cheap, colourful cotton cloth from India. English weavers, spinners and dyers petitioned Parliament, which in 1700 kept most printed Indian cotton from being worn or used, then in 1721 banned the sale of most cotton cloth at all.","kidsLink":"Even with spinning wheels, cloth made in England lost buyers to cheap, colorful cotton cloth from India. English cloth-makers were upset, so Parliament passed laws in 1700 and 1721 to keep most cotton cloth out of English shops and clothes.","minAge":4},{"event":"lombe-silk-mill-1721","year":1721,"label":"Lombe's silk mill, perhaps the first true factory","emoji":"🧵","link":"The same year, at Derby, something new was running: John Lombe and his half-brother Thomas's water-powered mill, twisting silk into thread by machine with hundreds of workers under one roof — probably the first fully mechanised factory in the world.","kidsLink":"That same year in England, John and Thomas Lombe opened a giant mill where a water wheel ran machines that twisted silk thread. It may have been the world's first factory where machines did the work.","minAge":4},{"event":"kay-flying-shuttle-1733","year":1733,"label":"The flying shuttle speeds up weaving","emoji":"🚀","link":"Lombe's mill twisted silk thread by water power; weaving was still slow handwork. John Kay's flying shuttle sped it up, letting one weaver fling the shuttle across the loom and weave roughly twice as fast — so fast that spinners suddenly couldn't keep up.","kidsLink":"Lombe's mill used machines to twist silk. Weaving was still slow until John Kay's flying shuttle let one weaver fling the shuttle across the loom about twice as fast — so fast that spinners couldn't make thread quickly enough.","minAge":4},{"event":"dhaka-s-muslin-is-woven-fine-as-air","year":1750,"label":"Dhaka's Muslin Is Woven Fine As Air","emoji":"🧵","link":"While English weavers raced to speed up their looms, Dhaka's weavers spun cotton so fine that travellers said a whole sheet of their muslin could be pulled through a ring — 'woven air', prized by Mughal emperors and European nobility.","kidsLink":"While English weavers were speeding up their looms, weavers in Dhaka were making amazing cloth: cotton so fine a whole sheet could pass through a ring. People called it 'woven air.'","minAge":4},{"event":"spinning-jenny-1764","year":1764,"label":"The spinning jenny","emoji":"🧵","link":"Dhaka's muslin showed how fine cotton could be spun; back in England, the urgent problem was that spinners could not keep up with the new flying-shuttle looms. James Hargreaves' spinning jenny let one worker spin many threads at once.","kidsLink":"Dhaka's weavers made amazingly fine thread. In England, spinners still couldn't keep up with the new fast looms. James Hargreaves invented the spinning jenny, letting one worker spin many threads at once.","minAge":4},{"event":"water-frame","year":1769,"label":"Arkwright's water frame spins by water power","emoji":"💧","link":"The jenny let one worker spin many threads; Richard Arkwright's water frame went further, using a flowing river to spin strong cotton thread without tiring human hands and helping move cloth-making into powered factories.","kidsLink":"The spinning jenny helped one worker spin many threads. Richard Arkwright's water frame used a flowing river to spin strong cotton thread, so hands did not tire.","minAge":4},{"event":"arkwright-cromford-mill-1771","year":1771,"label":"Cromford Mill, the first water-powered cotton factory","emoji":"💧","link":"The water frame needed a home. At Cromford, Richard Arkwright built a mill powered by water from a lead-mine drain and Bonsall Brook, running his water frames day and night with shifts of workers, many of them children. It was widely copied.","kidsLink":"The water frame needed a place to work. Richard Arkwright built Cromford Mill, powered by flowing water, and ran machines day and night. Many other factories copied it.","minAge":4},{"event":"cartwright-power-loom-1785","year":1785,"label":"The power loom mechanises weaving at last","emoji":"🧶","link":"Arkwright had mechanised spinning; weaving still depended on a weaver's hands and feet. Edmund Cartwright, a clergyman, patented a loom driven by machinery instead — crude at first, but the beginning of mechanised weaving, improved over the following decades into reliable automatic looms.","kidsLink":"Arkwright's mill made spinning thread faster with machines. Weaving cloth was still done by hand until Edmund Cartwright, a clergyman, patented a loom worked by machinery. It was clumsy at first, but better machine looms grew from his idea.","minAge":4},{"event":"cotton-gin-patented","year":1793,"label":"Cotton Gin Invented","emoji":"🌱","link":"Machines could now spin and weave cotton fast. In 1793 Eli Whitney applied to patent a cotton gin that cleaned the seeds from short-staple cotton; cotton farming became hugely profitable — and planters bought more enslaved people to grow and pick it, entrenching slavery in the American South.","minAge":10},{"event":"jacquard-loom-punchcards-1804","year":1804,"label":"The Jacquard loom weaves with punched cards","emoji":"🃏","link":"Cotton gins were solving how to prepare raw fibre faster; in France, Joseph Marie Jacquard tackled a different problem — how to weave complicated patterns that had needed a weaver and a helper. His loom, controlled by chains of punched cards, wove them automatically.","kidsLink":"Cartwright's loom was run by a machine. In France, Joseph Marie Jacquard found another way to help weavers: a loom that used punched cards to weave fancy patterns all by itself.","minAge":4},{"event":"factory-act-child-labour-1833","year":1833,"label":"Britain limits child labour in factories","emoji":"🧒","link":"Britain's spinning and weaving mills ran on the labour of children as well as adults — many of Arkwright's shift workers had been children. The Factory Act of 1833 banned children under nine from textile mills except silk mills, capped older children's hours and created inspectors to enforce it.","minAge":10},{"event":"howe-sewing-machine-1846","year":1846,"label":"Howe patents his sewing machine","emoji":"🪡","link":"Factory law limited who could work in the mills, but new machines kept coming. In 1846 Elias Howe patented a lockstitch sewing machine; machines like his could sew a shirt in about an hour instead of 14 by hand, and clothing makers used them to produce the first ready-to-wear clothes.","kidsLink":"Jacquard's loom could weave fancy patterns by itself. Years later, Elias Howe invented a sewing machine. Machines like it could sew a shirt in about an hour instead of 14 by hand, so factories could make lots of ready-made clothes.","minAge":4},{"event":"singer-sewing-machine-patent-1851","year":1851,"label":"Singer patents his sewing machine","emoji":"🪡","link":"Howe was not the last to patent a sewing machine. On August 12, 1851, Isaac Singer received US Patent 8294 for improvements; his success came from its practicality, ease of home use and installment payments.","kidsLink":"After Elias Howe, Isaac Singer won a patent in 1851 for a better sewing machine. People could use it at home and pay for it in installments.","minAge":4},{"event":"mauveine-synthetic-dye","year":1856,"label":"Mauveine, the first commercial synthetic dye","emoji":"🎨","link":"Machines could now weave and sew cloth fast; colour still came from natural sources such as indigo plants and sea snails. In 1856, teenage chemist William Perkin was trying to make medicine when he accidentally created mauveine, the first synthetic dye to be sold — launching a whole industry of colours made by chemistry.","kidsLink":"Machines could now weave and sew cloth quickly. Colors still came from plants and animals until a teenage chemist accidentally made a bright purple dye from chemicals. It was one of the very first colors made this way.","minAge":4},{"event":"triangle-shirtwaist-fire-1911","year":1911,"label":"The Triangle Shirtwaist fire","emoji":"🧵","link":"Ready-to-wear clothes were now sewn by machine. In 1911, fire tore through a crowded New York garment factory where the doors had been locked; 146 workers, mostly young immigrant women and girls, died, and the outcry led New York to pass new laws to make factories safer.","minAge":10},{"event":"gandhi-non-cooperation-movement-1920","year":1920,"label":"Gandhi's Non-Cooperation Campaign","emoji":"✊","link":"After the Triangle fire, cloth's story turns to protest. Under British rule, Indian raw cotton was bought cheaply, shipped to Manchester for processing and sold back in India. From September 1920 Gandhi's Non-Cooperation Movement boycotted English-made goods, especially clothing, and urged Indians to spin khadi on the charkha and abandon foreign clothes.","minAge":10},{"event":"nylon-first-synthetic-fiber-1935","year":1935,"label":"Wallace Carothers makes nylon","emoji":"🧪","link":"Gandhi had urged Indians to spin khadi by hand; in America, chemists were pushing fibre in the opposite direction. In 1935, Wallace Carothers made the first nylon, a fibre announced as made from coal, water and air — no plant or animal involved at all.","kidsLink":"The purple dye came from chemistry. Years later, a scientist named Wallace Carothers used chemistry to make a whole new thread, nylon, from coal, water and air instead of a plant or animal.","minAge":4},{"event":"polyester-1941","year":1941,"label":"Polyester, the wrinkle-resistant fabric","emoji":"👚","link":"Nylon had shown fibre could be made in a lab instead of grown on a farm. In 1941, British chemists John Whinfield and James Dickson patented the most common kind of polyester, a fabric that resists wrinkling and shrinking in the wash — now used in shirts, trousers, jackets and hats.","kidsLink":"Nylon showed that thread didn't need a farm at all. In 1941, two chemists invented a new kind of polyester that barely wrinkles or shrinks, so today it's in shirts, jackets and hats.","minAge":4},{"event":"fast-fashion","year":1990,"label":"Fast fashion floods the world with cheap clothes","emoji":"🛍️","link":"Fibre could now be made in a lab and clothes sewn by machine. In the late 20th century, clothing chains began copying the latest trends quickly and selling them very cheaply through fast mass production — making trends cheap, but leaving mountains of textile waste and pollution.","kidsLink":"Now thread could be made in a lab. Later, clothing stores started copying new styles super fast and selling them very cheaply. But making so many clothes so quickly left mountains of waste.","minAge":4},{"event":"rana-plaza-collapse-2013","year":2013,"label":"The Rana Plaza Collapse","emoji":"🧵","link":"Someone still had to sew those cheap clothes. On 24 April 2013 the nine-story Rana Plaza building near Dhaka, home to five garment factories making clothing for international brands, collapsed, killing 1,134 people; afterwards more than 200 global brands joined unions in a building-safety accord.","minAge":10}]},{"id":"how-we-mapped-the-world","title":"How we mapped the world","emoji":"🗺️","blurb":"A map is only as good as your ability to fix a position on it. From a clay tablet of settlements, streams and hills to satellites that can tell you where you are almost anywhere on Earth, this is the four-thousand-year argument over how anyone actually knows where they are — and what empires, traders, and curiosity were willing to pay to find out.","minAge":7,"kidsCut":true,"lens":"explore","group":"travel-and-messages","beats":[{"event":"oldest-known-map-nuzi","year":-2300,"label":"One of the oldest known maps — drawn in clay","emoji":"🗺️","link":"Long before anyone could measure the whole Earth, people were already shrinking pieces of it onto something portable: this clay tablet from Nuzi shows settlements, streams and hills, and names its directions by their winds - one of the oldest known maps. Every map since is the same trick at a bigger scale.","kidsLink":"This clay tablet is one of the oldest maps anyone has found. Every map made after it, even the ones on your phone, does the same job: showing a real place in a smaller way.","minAge":4},{"event":"babylonian-imago-mundi","year":-600,"label":"The Babylonian Map of the World","emoji":"🌍","link":"Some seventeen centuries later the same clay-tablet habit scaled up from one patch of land to everything there was: the Babylonians drew the whole known world as a disc, their own city near the center and an ocean ringing the edge. It was a picture of the whole known world, but no way to say how big any of it was.","kidsLink":"Centuries later, people used clay tablets again. This time they drew the whole world as a circle, with their own city near the middle.","minAge":4},{"event":"anaximander-of-miletus","year":-560,"label":"Anaximander maps the world","emoji":"🌍","link":"Around the same era, in the Greek city of Miletus, Anaximander drew his own map of the known world - and went beyond drawing it, reasoning that the Earth floats freely in space and looking for natural causes rather than the will of the gods.","kidsLink":"Not long after, a Greek thinker named Anaximander also drew a map of the world. Instead of explaining things with gods and myths, he tried to explain Earth using reasons and logic.","minAge":4},{"event":"eratosthenes","year":-240,"label":"Measuring the Earth","emoji":"🌍","link":"How big the Earth actually was got an answer in Alexandria. Eratosthenes, the city's chief librarian, used shadows to calculate Earth's circumference with astonishing accuracy, turning every later map into a fraction of something measurable.","kidsLink":"About three hundred years later, a librarian named Eratosthenes had an idea. He used shadows and math to measure the size of the whole Earth. His answer was very close to correct.","minAge":4},{"event":"mawangdui-silk-maps","year":-168,"label":"Silk maps buried in a Han tomb","emoji":"🗺️","link":"While Alexandria worked out the Earth's size, mapmakers in Han China were charting their own land: three silk maps - topographic, military and prefecture - buried in 168 BCE with a man believed to be a relative of the Marquis of Dai, mark the border between the Han and the Nanyue kingdom.","kidsLink":"Far away in China, people were making their own maps. Three maps drawn on silk were buried in a tomb in 168 BCE. They show the land and the border with a neighbouring kingdom.","minAge":7},{"event":"ptolemy-s-geography-maps-the-world","year":150,"label":"Ptolemy's Geography Maps The World","emoji":"🗺️","link":"Back in Alexandria, about four centuries after Eratosthenes, Claudius Ptolemy pushed the Greek approach further, listing places across the known world by latitude and longitude and setting conventions that guided mapmakers for more than a thousand years.","kidsLink":"Back in Alexandria, a man named Ptolemy wrote a book. It gave each place he knew two numbers. The numbers showed where it lay on Earth.","minAge":4},{"event":"pei-xiu-grid-maps","year":267,"label":"Pei Xiu builds maps on a grid in China","emoji":"▦","link":"A century later and far to the east, the Chinese official Pei Xiu set out six principles of his own for accurate maps, among them a rectangular grid and a graduated scale so distances and directions stayed correct.","kidsLink":"About a hundred years later, in China, an official named Pei Xiu said to draw maps on a grid of squares. That way, distances and directions stayed correct.","minAge":4},{"event":"polynesian-wayfinding-double-canoe","year":700,"label":"Wayfinders read the stars across the Pacific","emoji":"⭐","link":"Grids and written coordinates were one way to fix a place; out in the Pacific, voyagers found their way with no instruments at all. Navigators read the stars, swells, clouds and birds, and with knowledge passed down by memory found tiny islands scattered across the vast Polynesian Triangle.","kidsLink":"While mapmakers in China and Greece drew maps, Pacific sailors found their way differently. They used no instruments at all. They remembered the stars, the waves and the birds.","minAge":4},{"event":"al-biruni-measures-earth-s-radius-from-a-mountai","year":1037,"label":"Al-Biruni Measures Earth's Radius from a Mountain","emoji":"⛰️","link":"Centuries later, the scholar al-Biruni returned to Eratosthenes' question of how big the Earth is, but needed only one place to stand: climbing a single mountain and measuring the dip of the horizon, he worked out Earth's radius to a value close to today's figure.","kidsLink":"Centuries later, a scholar named al-Biruni measured the size of the Earth in a new way. He climbed one mountain, measured the horizon, and used math to work it out.","minAge":4},{"event":"the-compass-guides-ships-at-sea","year":1119,"label":"The compass guides ships at sea","emoji":"🧭","link":"Knowing the Earth's size was one problem; knowing which way you were pointed was another. In China, sailors had begun relying on a different tool: the magnetized needle, described by Shen Kuo in 1088 and, within a few decades, recorded steering ships in dark weather.","kidsLink":"Knowing how big the Earth is didn't help sailors steer in dark weather. In China, sailors began using a new tool instead: a magnetic compass, to show them which way was which even when they couldn't see the stars.","minAge":4},{"event":"yu-ji-tu-gridded-map","year":1142,"label":"Yu Ji Tu: China's oldest surviving gridded map","emoji":"▦","link":"The grid Pei Xiu had written about some nine centuries earlier survives on stone here: the Yu Ji Tu, a map of China carved in 1142 and covered in a lattice of squares, is the earliest surviving Chinese map to carry one.","kidsLink":"Long before, Pei Xiu had said to draw maps on a grid. This stone map of China is the oldest Chinese map with a grid that still survives.","minAge":4},{"event":"al-idrisi-s-world-map","year":1154,"label":"Al-Idrisi's World Map","emoji":"🗺️","link":"Across Asia and the Mediterranean, knowledge was piling up - Ptolemy's coordinates, what Muslim traders had learned of Africa, the Indian Ocean and the Far East. At the Norman court of Sicily, the geographer al-Idrisi combined it into the Tabula Rogeriana, one of the most advanced world maps of the Middle Ages.","kidsLink":"A dozen years later, in Sicily, a geographer named al-Idrisi mixed Ptolemy's old book with what Muslim traders and explorers had learned. The result was one of the best world maps drawn so far.","minAge":4},{"event":"portolan-charts","year":1280,"label":"Portolan charts: sailing by compass lines","emoji":"⚓","link":"A different, more practical Mediterranean tradition was rising alongside these scholarly world maps: sailors' portolan charts, crossed with compass lines that showed a captain which direction to steer from one harbor to the next, rather than depicting the whole known world.","kidsLink":"Around the Mediterranean Sea, sailors were making a different kind of map. Instead of showing the whole world, these charts were covered in crossing lines that showed ships which way to steer from port to port.","minAge":4},{"event":"kangnido-world-map","year":1402,"label":"The Kangnido maps East and West together","emoji":"🌏","link":"Far from Mediterranean sailing charts, Korean scholars were compiling their own view of the whole world: the Kangnido drew on Chinese maps and Islamic geographic knowledge to put China and an enlarged Korea at its center, with Japan to the east, while still including India, Arabia, Africa and Europe.","kidsLink":"Far away in Korea, mapmakers combined what they knew from China and the Islamic world. They drew their own map of everywhere, with China and a big Korea in the middle.","minAge":4},{"event":"waldseemuller-map","year":1507,"label":"The map that first named 'America'","emoji":"🌎","link":"A century later, what 'the whole world' meant was changing: Martin Waldseemüller drew the New World onto his world map and, naming it after the explorer Amerigo Vespucci, became the first to label it 'America'.","kidsLink":"A hundred years later, a mapmaker named Waldseemüller drew a new map of the world. It was the first map to call the New World by the name America.","minAge":4},{"event":"magellan-expedition-circles-globe","year":1522,"label":"Magellan Expedition Circles Globe","emoji":"🧭","link":"Waldseemüller's map put the New World on paper - but no ship had yet sailed all the way around the world. Setting out from Spain in 1519, the Magellan-Elcano expedition did it, completing the first circumnavigation of the Earth in 1522 and revealing the vast size of the Pacific.","kidsLink":"No ship had ever sailed all the way around the Earth. Some years later, one group of ships from Spain did it, for the very first time.","minAge":4},{"event":"mercator-projection","year":1569,"label":"Mercator's projection for straight-line sailing","emoji":"🗺️","link":"Now that ships were making these long ocean crossings, navigators needed an easier way to steer a course over such distances. Gerardus Mercator's projection flattened the round Earth so a straight compass bearing on the map matched a straight course at sea, at the cost of distorting size near the poles.","kidsLink":"Now that ships were sailing all over the globe, sailors needed an easier way to steer in straight lines. Mapmaker Mercator found a way to flatten the round Earth onto paper that made this possible.","minAge":4},{"event":"ortelius-publishes-the-first-modern-atlas","year":1570,"label":"Ortelius Publishes The First Modern Atlas","emoji":"📖","link":"The very next year, in Antwerp, Abraham Ortelius gathered maps drawn on uniform sheets into one bound volume - the Theatrum Orbis Terrarum, credited as the world's first modern atlas.","kidsLink":"The very next year, a mapmaker named Abraham Ortelius collected many maps into one book. It is thought of as the world's first modern atlas.","minAge":4},{"event":"snellius-triangulation","year":1615,"label":"Snell measures the land by triangulation","emoji":"📐","link":"Maps could now be projected and compiled, but distances on them often still rested on rough estimates. Dutch scientist Willebrord Snell changed that: using a chain of triangles between church towers, he measured a degree of latitude in the western Netherlands and from it the size of the Earth, to within about 3.5%.","kidsLink":"Maps looked good, but the distances on them were often rough guesses. A scientist named Snell found a way to measure land carefully, using triangles between tall church towers.","minAge":4},{"event":"longitude-act-20000-prize","year":1714,"label":"Britain offers up to £20,000 for finding longitude","emoji":"🧭","link":"Measuring land was one thing; at sea, sailors still could not tell how far east or west they were, and ships could be wrecked. In 1714 the British Parliament offered rewards of up to £20,000 for a practical way to find longitude at sea.","kidsLink":"Even with better maps, sailors still had a big problem: they couldn't tell how far east or west their ship had traveled. Britain offered huge prizes, up to £20,000, to whoever could solve it.","minAge":7},{"event":"geodesic-mission-shape-of-earth","year":1739,"label":"Measuring the Shape of the Earth in the Andes","emoji":"📐","link":"While Britain's prize chased a way to fix position at sea, a separate expedition tackled a related unknown: the Earth's own shape. French astronomers and Spanish officers travelled to the Andes near Quito and, by 1739, had measured an equatorial arc that helped show the planet is flattened at the poles.","kidsLink":"Around the same time, other scientists were asking a different question: what shape is the Earth, exactly? They traveled to the Andes Mountains and measured carefully, and found out it isn't a perfect ball.","minAge":4},{"event":"harrison-marine-chronometer-longitude","year":1761,"label":"Harrison's sea clock solves longitude","emoji":"⏱️","link":"The answer came not from an astronomer but from a carpenter. John Harrison built a clock accurate enough to survive a rolling, damp voyage, and comparing its steady home time to local noon let a ship work out how far east or west it had sailed - though he was paid only in parts, never the official prize.","kidsLink":"The answer finally came from a carpenter, not a scientist. John Harrison built a clock that kept very accurate time even on a rocking ship, so sailors could work out how far east or west they had sailed.","minAge":4},{"event":"cassini-map-france","year":1793,"label":"The Cassini map: a whole country surveyed","emoji":"🇫🇷","link":"On land, meanwhile, chains of triangles like Snell's were put to work on a whole country. Four generations of the Cassini family triangulated France over more than sixty years, producing the first topographic map of the whole kingdom and the first built on a geodesic triangulation.","kidsLink":"On land, mapmakers used Snell's triangles to measure a whole country. One family spent four generations surveying France. It became the first careful map of the whole country.","minAge":4},{"event":"great-trigonometrical-survey","year":1802,"label":"The Great Trigonometrical Survey of India","emoji":"🏔️","link":"Britain then aimed that same method at a subcontinent. Starting from a baseline near Madras in 1802, the Great Trigonometrical Survey ran chains of precise triangles across India for nearly 70 years, measuring the heights of Himalayan giants.","kidsLink":"Britain then used that same triangle method on a bigger scale. It spent almost 70 years measuring India with long chains of triangles.","minAge":4},{"event":"peak-xv-is-confirmed-the-world-s-highest","year":1856,"label":"Peak XV Is Confirmed The World's Highest","emoji":"🏔️","link":"That survey's most famous discovery came from calculation, not a climb. Working from its triangulated readings, its surveyors calculated that a remote Himalayan peak known only as 'Peak XV' stood taller than any other mountain on Earth - a fact patient measurement could reveal that no single eye ever could.","kidsLink":"That huge survey of India made its most famous discovery at a desk, not on a mountain. Careful measurements showed a faraway peak, called 'Peak XV,' was the tallest point on all of Earth.","minAge":4},{"event":"international-meridian-conference-1884","year":1884,"label":"The world picks one meridian","emoji":"🌐","link":"Countries still measured longitude from their own separate starting lines. In 1884, delegates from 26 nations met in Washington and agreed to share just one: the line through Greenwich, England, would be zero degrees longitude for the whole world.","kidsLink":"Different countries had been measuring from their own separate starting lines. In 1884, nations agreed to share just one: the line through Greenwich, England became the world's zero point.","minAge":4},{"event":"moore-brabazon-aerial-camera","year":1915,"label":"The first purpose-built aerial camera","emoji":"📷","link":"Three decades later, the next leap in mapmaking came from a new vantage point entirely: World War One aircraft. British officer John Moore-Brabazon built the first purpose-made aerial camera, and by comparing photos shot from different angles he could even show the height of things on the ground below.","kidsLink":"Thirty years later, a new way to make maps appeared: cameras in airplanes. An officer named Moore-Brabazon built one during World War One, and pairs of his photos could even show how tall things on the ground were.","minAge":7},{"event":"marie-tharp-ocean-floor","year":1957,"label":"Marie Tharp maps the ocean floor","emoji":"🌊","link":"Aerial cameras could map anything a plane could photograph, but most of the planet - the seafloor - stayed invisible from the air. Geologist Marie Tharp instead turned ship depth soundings into the first scientific map of the Atlantic floor, finding a rift valley along the mountain range down its middle.","kidsLink":"Cameras in planes could map land, but not what's under the ocean. Scientist Marie Tharp used depth measurements from ships instead. Her map showed a giant mountain range down the middle of the Atlantic Ocean, with a crack along it.","minAge":4},{"event":"landsat-1-earth-imaging","year":1972,"label":"Landsat 1 starts photographing the Earth","emoji":"📡","link":"Fifteen years later, mapping moved into orbit. NASA's Landsat 1, the first satellite launched just to watch over the planet, sent back more than 100,000 images covering over three-quarters of Earth's surface in its first two years.","kidsLink":"Fifteen years later, mapping moved into space. NASA launched a satellite whose only job was to photograph Earth's surface, again and again.","minAge":4},{"event":"gps-fully-operational","year":1995,"label":"GPS becomes fully operational","emoji":"📍","link":"Landsat could show you the world from above; GPS let the world tell you where you stood in it. With a full fleet of satellites overhead, anyone with a receiver could fix their position almost anywhere on Earth - the oldest question of all, answered instantly.","kidsLink":"Landsat could photograph the Earth from above. GPS went further. Once enough satellites circled overhead, anyone with a receiver could find out where they were, almost anywhere on the planet.","minAge":4},{"event":"google-earth-launch","year":2005,"label":"Google Earth puts the planet on a screen","emoji":"💻","link":"GPS could tell you your coordinates; Google Earth gave those coordinates a picture to sit inside. It stitched satellite imagery into an explorable 3D globe that anyone could fly around and zoom into, down to their own street.","kidsLink":"GPS could tell you exactly where you were, as numbers. Google Earth did something new: it let anyone fly around a picture of the whole planet and zoom right down to their own street.","minAge":4},{"event":"seabed-2030-maps-the-ocean-floor","year":2016,"label":"Seabed 2030 sets out to map the seafloor","emoji":"🌊","link":"Google Earth made the planet feel fully mapped, but beneath the oceans only about 6% of the seabed had been surveyed to modern standards. Seabed 2030 set out to finish the job Marie Tharp had begun, pooling ship, satellite and crowdsourced depth data into one complete map of the ocean floor.","kidsLink":"Google Earth made the whole planet feel explored, but underneath the ocean's surface, most of the seafloor still hadn't really been mapped. A project called Seabed 2030 set out to finally finish that job.","minAge":4}]},{"id":"what-the-sky-is","title":"How we worked out what the sky is","emoji":"🔭","blurb":"A child asks 'what ARE the stars?' — the real answer took nearly four thousand years, and it came not from clever guessing but from watching the sky more carefully than it wanted to be watched.","minAge":7,"kidsCut":true,"lens":"science","group":"sky-space-and-time","beats":[{"event":"babylonian-venus-tablet","year":-1646,"label":"Babylonian Venus Tablet","emoji":"🪐","link":"The story starts here because this is a very early record of a planet's motion: over 21 years, Babylonian observers noted exactly when Venus rose and set, turning a wandering light into something with a pattern worth tracking.","kidsLink":"Long ago in Babylon, people watched the sky. They wrote down when they saw the planet Venus rise and set, for 21 years.","minAge":4},{"event":"babylonian-astronomical-diaries","year":-652,"label":"Babylon begins its nightly sky diaries","emoji":"🌙","link":"Babylon's scribes kept watching. From the 7th century BCE they logged the Moon, planets and weather night by night, for centuries. A record that long is what finally lets you notice patterns — and predict what the sky will do next.","kidsLink":"Babylon kept on watching the sky. Later, scholars began writing sky diaries every night. They wrote about the moon and planets for hundreds of years.","minAge":4},{"event":"comet-recorded-spring-autumn-annals","year":-613,"label":"A comet enters the record books","emoji":"☄️","link":"Far to the east, China's record-keepers had taken up the same habit on their own: writing down what the sky did instead of trusting memory. In 613 BCE the annals of the state of Lu logged a comet — the earliest confirmed comet sighting in China's long run of records.","kidsLink":"Far away in China, people were writing down the sky too. In 613 BCE they wrote about a comet. It is the oldest comet sighting in China's records we can be sure of.","minAge":4},{"event":"anaxagoras-cosmic-mind","year":-450,"label":"Anaxagoras and the Cosmic Mind","emoji":"☀️","link":"Records like Babylon's diaries and China's annals were data, not explanation; someone still had to say what the lights actually were. In Athens, Anaxagoras said the Sun is a blazing mass of red-hot metal, larger than the Peloponnese, and the Moon shines by its light — ideas that got him charged with impiety.","kidsLink":"Before this, people had mostly written down what the sky did. Anaxagoras tried to say what the lights really were. He said the Sun was a huge ball of glowing hot metal.","minAge":7},{"event":"aristarchus-puts-sun-at-center","year":-280,"label":"Aristarchus Puts Sun At Center","emoji":"☀️","link":"Greek thinkers kept treating the sky as something to reason about rather than worship. Aristarchus of Samos pushed that further than anyone yet, proposing that the Earth itself moves, circling the Sun and spinning on its axis — about eighteen centuries before Copernicus.","kidsLink":"Other Greek thinkers kept asking big questions about the sky. Aristarchus guessed that the Earth circles the Sun, not the other way around.","minAge":4},{"event":"hipparchus-discovers-precession","year":-127,"label":"Hipparchus notices the sky itself is shifting","emoji":"⭐","link":"Aristarchus's idea won few followers; most astronomers kept the Earth at the centre and got on with measuring. Hipparchus measured with great care — and when he compared his star positions with records made over a century earlier, they did not line up. The stars were slowly drifting against the seasons.","kidsLink":"Most people still believed the Earth sat in the middle. Hipparchus compared old star records with his own, and saw that the stars had slowly shifted compared to the seasons.","minAge":4},{"event":"ptolemy-s-almagest","year":150,"label":"Ptolemy's Almagest","emoji":"🔭","link":"Building on Hipparchus's models and star catalogue, Ptolemy in Alexandria wrote one vast Earth-centred model of the heavens, with tables precise enough to predict the planets — an answer so useful it was accepted for more than 1,200 years.","kidsLink":"Ptolemy used Hipparchus's star work to build a huge system with Earth in the middle. His tables predicted the planets so well that people used them for more than 1,200 years.","minAge":4},{"event":"aryabhata-s-astronomy","year":499,"label":"Aryabhata's Astronomy","emoji":"🌌","link":"In India, Aryabhata offered a different reading of the same nightly motion: the stars' daily turn, he said, is really the Earth spinning on its axis. Aristarchus had thought so too, but centuries earlier and far to the west.","kidsLink":"In India, the astronomer Aryabhata had a different idea. Maybe the sky is not turning each night. Maybe the Earth itself is spinning.","minAge":4},{"event":"al-sufi-s-star-geometry","year":964,"label":"Al-Sufi's Star Geometry","emoji":"🌠","link":"Better records also turned up things nobody had explained yet. Cataloguing the stars with unusual care, the Persian astronomer al-Sufi noted a faint, fixed smudge of light that was not a star at all — just a 'small cloud.' No one would know what it really was for nearly a thousand years.","kidsLink":"Astronomers kept mapping the stars carefully. In Persia, al-Sufi saw a strange fuzzy patch of light and called it a 'small cloud.' It was really the Andromeda Galaxy.","minAge":4},{"event":"crab-nebula-supernova","year":1054,"label":"Crab Nebula Supernova","emoji":"🦀","link":"Al-Sufi's 'small cloud' showed that patient stargazers could find things no one expected. About ninety years later, Chinese astronomers recorded something even harder to miss: a new star bright enough to see in daylight, whose scattered remains would one day be named the Crab Nebula.","kidsLink":"Al-Sufi had spotted a strange smudge of light. Later, astronomers in China saw something even stranger: a brand-new star so bright it could be seen in daylight.","minAge":4},{"event":"maya-venus-tables-dresden-codex","year":1200,"label":"Maya Venus Tables of the Dresden Codex","emoji":"📜","link":"While astronomers in Asia were logging exploding stars, another tradition was independently tracking the sky just as carefully. Maya scribes, probably in the Yucatan, painted the Dresden Codex, whose detailed tables followed Venus's movements much as the Babylonians had, an ocean and centuries apart.","kidsLink":"Far away in the Americas, Maya scribes were watching the sky too. They painted a book with tables that tracked the planet Venus, just like the Babylonians once did.","minAge":4},{"event":"tusi-couple-planetary-motion","year":1247,"label":"The Tusi Couple","emoji":"🪐","link":"Meanwhile, astronomers were still working on Ptolemy's Earth-centred model. In a commentary on the Almagest, al-Tusi described a geometric trick — a small circle rolling inside a larger one — later used widely to model planetary motion without Ptolemy's awkward 'equant' point.","kidsLink":"Ptolemy's old system had an awkward part in its math. Al-Tusi found a clever trick with two circles. Later astronomers used it to show how planets move without that awkward part.","minAge":4},{"event":"copernicus-heliocentrism","year":1543,"label":"A Sun-centred universe","emoji":"☀️","link":"Nearly three centuries later, Copernicus used a device very like al-Tusi's — some historians think he learned of it — and argued the planets' motions made more sense with the Sun, not the Earth, at the centre. The heavens hadn't changed; the explanation had.","kidsLink":"Much later, Copernicus used a trick very like al-Tusi's. He argued that the Sun belongs at the center, not the Earth.","minAge":4},{"event":"tycho-s-new-star","year":1572,"label":"Tycho's New Star","emoji":"⭐","link":"Copernicus had moved the Earth, but the heavens beyond the Moon were still thought perfect and unchanging. Then Tycho Brahe observed a brilliant new star in Cassiopeia — a change in the very heavens that were never supposed to change, and a direct challenge to that ancient belief.","kidsLink":"People also believed the stars far away never changed. Then Tycho Brahe saw a brand-new star appear in the sky, and showed that the heavens really can change.","minAge":4},{"event":"kepler-first-two-laws-1609","year":1609,"label":"Kepler's laws of planetary motion","emoji":"🪐","link":"Tycho's observatory had gathered unusually accurate planetary data, but Tycho died unexpectedly in 1601. Kepler, whom he had set to analysing those observations, succeeded him and found they only fit if planets moved in ellipses, not perfect circles, sweeping out equal areas in equal times.","kidsLink":"Tycho collected very careful measurements before he died. Kepler used that data. He found that planets travel in oval paths, not circles.","minAge":4},{"event":"galileo-telescope-1610","year":1610,"label":"Galileo turns a telescope skyward","emoji":"🔭","link":"Kepler had worked from measurements and mathematics alone; the next step was simply seeing more. Galileo pointed a telescope at Jupiter and watched moons circling a world that was plainly not the Earth — visible evidence that not everything in the sky goes round us.","kidsLink":"Kepler had worked out the planets' paths using just measurements and math. The next year, Galileo pointed a new telescope at the sky and actually saw moons circling Jupiter.","minAge":4},{"event":"newton-s-universal-gravitation","year":1687,"label":"Newton's Universal Gravitation","emoji":"🍎","link":"Seeing that other bodies had their own orbiting moons raised an obvious question: what actually holds anything in orbit at all? Newton answered it with one law of gravitation that pulled an apple to the ground and held the Moon in its path by the very same force.","kidsLink":"Galileo had seen other worlds with their own moons. Newton then figured out the one force, gravity, that holds all of those moons and planets in their orbits.","minAge":4},{"event":"herschel-uranus-1781","year":1781,"label":"Herschel discovers Uranus","emoji":"🔵","link":"Newton's law explained how the known planets moved, but nobody knew whether there were more to find. Nearly a century later, William Herschel, sweeping the sky with a homemade telescope, found an entirely new planet beyond Saturn — the first since antiquity — doubling the known size of the solar system.","kidsLink":"Newton's law explained how planets orbit. William Herschel built his own telescope and found a brand-new planet: Uranus.","minAge":4},{"event":"fraunhofer-lines-1814","year":1814,"label":"Fraunhofer finds dark lines in sunlight","emoji":"🌈","link":"Herschel's homemade telescope had shown telescopes could still find new worlds, but no telescope could show what a star was made of. Joseph von Fraunhofer spread sunlight into a rainbow and found hundreds of dark lines crossing it — a code nobody could read yet, but one that would later reveal the stars' chemistry.","kidsLink":"Herschel had shown that telescopes could find whole new planets. Fraunhofer found something different: strange dark lines hidden in sunlight. No one could explain them yet.","minAge":4},{"event":"first-measured-star-distance","year":1838,"label":"First Measured Star Distance","emoji":"📏","link":"Meanwhile an older question was finally cracked: how far away are the stars? Friedrich Bessel caught the star 61 Cygni's tiny yearly shift against the background sky and turned it into the first reliable distance to another star — the sky gained actual depth.","kidsLink":"Another puzzle was how far away the stars are. Friedrich Bessel used careful measurements to work out the distance to a nearby star for the first time.","minAge":4},{"event":"kirchhoff-reads-starlight","year":1859,"label":"Kirchhoff Reads Starlight","emoji":"🌈","link":"Bessel had shown how far the stars were, but Fraunhofer's dark lines from decades earlier were still an unsolved puzzle. Gustav Kirchhoff and Robert Bunsen finally cracked it, showing those lines reveal which chemical elements are present — letting astronomers read what distant stars are made of from their light alone.","kidsLink":"Bessel had measured how far away a star was. Kirchhoff and Bunsen then figured out that the dark lines Fraunhofer saw actually reveal which elements are inside a star.","minAge":4},{"event":"leavitt-finds-a-yardstick-for-the-universe","year":1912,"label":"Leavitt Finds a Yardstick for the Universe","emoji":"⭐","link":"Kirchhoff and Bunsen could now read a star's ingredients, but the universe's larger distances still needed a ruler. At Harvard, Henrietta Swan Leavitt found that pulsating Cepheid stars have a fixed link between brightness and pulsation period — a way to measure vast cosmic distances.","kidsLink":"Kirchhoff and Bunsen had learned to read what stars are made of. Henrietta Swan Leavitt found a different tool: a pulsing star that reveals how bright it truly is, for measuring bigger distances.","minAge":4},{"event":"galaxies-beyond-the-milky-way","year":1925,"label":"Galaxies Beyond The Milky Way","emoji":"🌌","link":"Leavitt's yardstick was the tool needed to work out what the faint 'nebulae' were — al-Sufi's 'small cloud' among them. Edwin Hubble used Cepheid stars to show the Andromeda 'nebula' lay far outside the Milky Way: our galaxy is just one of many.","kidsLink":"Leavitt's pulsing stars gave astronomers a way to measure huge distances. Edwin Hubble used that tool to prove a fuzzy patch of light was actually a whole separate galaxy.","minAge":4},{"event":"cecilia-payne-reveals-what-stars-are-made-of","year":1925,"label":"Cecilia Payne Reveals What Stars Are Made Of","emoji":"⭐","link":"While Hubble mapped how far the galaxies lay, a question from Kirchhoff's spectral code was still unanswered: what exactly are stars made of? In her 1925 thesis, Cecilia Payne showed stars are made mostly of hydrogen — a result senior scientists at first dismissed, until later observations proved her right.","kidsLink":"At the same time Hubble was studying galaxies, Cecilia Payne was studying starlight. In 1925 she showed that stars are made mostly of hydrogen, though other scientists doubted her at first.","minAge":4},{"event":"lemaitre-expanding-universe-1927","year":1927,"label":"Lemaitre proposes an expanding universe","emoji":"🌌","link":"With other galaxies confirmed real and impossibly distant, the universe itself was next. Working in Belgium, Georges Lemaitre used Einstein's equations of general relativity to argue in 1927 that the universe is expanding — though his paper, in a journal few astronomers outside Belgium read, made little impact.","kidsLink":"Now that other galaxies were known to be real, Georges Lemaitre used Einstein's equations to argue that the whole universe is growing bigger. Hardly anyone read his paper at first.","minAge":4},{"event":"hubble-shows-the-universe-is-expanding","year":1929,"label":"Hubble Shows the Universe Is Expanding","emoji":"🌌","link":"Lemaitre's argument for expansion had gone largely unnoticed. Two years later, working with the Mount Wilson telescope, Edwin Hubble confirmed the pattern Lemaitre had proposed: the farther a galaxy, the faster it moves away from us — now called Hubble's law, a sign the universe itself is expanding.","kidsLink":"Lemaitre's idea about a growing universe had barely been noticed. Two years later, Edwin Hubble found that the farther away a galaxy is, the faster it races away. It was a sign the universe is growing.","minAge":4},{"event":"bethe-explains-stellar-fusion-1939","year":1939,"label":"Bethe explains why stars shine","emoji":"⭐","link":"Payne had shown stars are made mostly of hydrogen, but not how they shine. Hans Bethe worked out the nuclear reaction chains — hydrogen fusing into helium — that explain how the Sun and other stars make their energy.","kidsLink":"Payne had shown that stars are made of hydrogen. Hans Bethe figured out why that matters: deep inside a star, hydrogen fuses together and lets off huge amounts of energy.","minAge":4},{"event":"cosmic-microwave-background","year":1964,"label":"Cosmic Microwave Background","emoji":"📡","link":"If Lemaitre and Hubble were right that the universe is expanding, the early universe must have been more compact and much hotter. In 1964 Arno Penzias and Robert Wilson detected a faint microwave glow filling all space — the afterglow of the Big Bang, and key evidence for it.","kidsLink":"If the universe is growing, then long ago everything must have been squeezed together and very hot. In the 1960s, two scientists found a leftover glow from that hot start, filling all of space.","minAge":4},{"event":"first-exoplanet-around-a-sun","year":1995,"label":"First Exoplanet Around A Sun-Like Star","emoji":"🪐","link":"By now much about the stars and the universe's beginning had been worked out, and an old question could be tested: do other stars, like our Sun, have planets of their own? In 1995 Michel Mayor and Didier Queloz found 51 Pegasi b, the first known planet orbiting a Sun-like star.","kidsLink":"By now scientists understood a lot about stars and the universe. In 1995, two astronomers found the very first planet known to circle a star like our Sun.","minAge":4},{"event":"the-accelerating-universe","year":1998,"label":"The Accelerating Universe","emoji":"🌠","link":"The universe was known to be expanding from a hot beginning, and most assumed gravity should be slowing that expansion down over time. In 1998 two teams studying distant exploding stars found the opposite: the expansion is speeding up, pointing to a mysterious dark energy.","kidsLink":"Scientists knew the universe was expanding and figured it should be slowing down. In 1998, they discovered the opposite: the expansion is actually speeding up.","minAge":4},{"event":"james-webb-2022","year":2022,"label":"James Webb Space Telescope","emoji":"🔭","link":"Dark energy showed the universe's story is still unfolding, and its earliest chapters were still the hardest to see. In 2022 the James Webb Space Telescope began revealing the earliest galaxies in stunning detail, carrying a nearly four-thousand-year habit of watching the sky closely into a new era.","kidsLink":"Even after all that, there was more to see. In 2022, the James Webb Space Telescope started showing us some of the earliest galaxies in amazing detail.","minAge":4}]},{"id":"women-who-changed-what-we-know","title":"Women who changed what we know","emoji":"🔬","blurb":"Named women across five continents and 4,000 years who added something to what humanity knows — a poem, a proof, a star, a cure — and what the rules of their time made them pay for it. The scarcity in the old stories is in the records and the rules, not in the women.","minAge":10,"kidsCut":true,"lens":"science","group":"people-and-ideas","beats":[{"event":"enheduanna-first-named-author","year":-2270,"label":"Enheduanna, First Named Author","emoji":"✍️","link":"In Sumer, a king's daughter served as high priestess at Ur, and temple hymns to the goddess Inanna carry her name. Scholars still debate whether she wrote them herself, but she is celebrated as the earliest named author we know of — for anybody.","kidsLink":"Old hymns to a goddess carry the name of Enheduanna, a priestess in Ur. She is often called the earliest writer whose name we know. So this journey about women and what we know begins with her.","minAge":4},{"event":"ban-zhao-finishes-book-of-han","year":100,"label":"Ban Zhao Helps Finish a Dynasty's History","emoji":"🖋️","link":"Enheduanna held her temple office as the daughter of the king. Over two thousand years later in Han China, Ban Zhao came to scholarship another way: when her brother died before finishing the dynasty's official history, she helped complete it, and later taught the empress at court.","kidsLink":"Long ago, old hymns carried Enheduanna's name. Much later in China, Ban Zhao helped finish her brother's history book. She became China's first known female historian.","minAge":7},{"event":"hypatia-teaches-alexandria","year":400,"label":"Hypatia teaches mathematics in Alexandria","emoji":"🔭","link":"Ban Zhao had helped write a dynasty's official history. About three centuries later in Alexandria, Hypatia taught mathematics, astronomy and philosophy to students, many of whom came from far away — the first woman mathematician whose life is reasonably well recorded.","kidsLink":"Ban Zhao helped write a history of China. Later, in Egypt, Hypatia taught math and astronomy in the city of Alexandria.","minAge":4},{"event":"fatima-al-fihri-founds-a-university-in-fez","year":859,"label":"Fatima al-Fihri founds al-Qarawiyyin in Fez","emoji":"📚","link":"More than four centuries after Hypatia taught in Alexandria, tradition says a merchant's daughter in Fez, Fatima al-Fihri, founded the mosque of al-Qarawiyyin. It grew into a great centre of learning, which UNESCO and Guinness World Records call the oldest place of higher learning still operating.","kidsLink":"Hypatia taught in Alexandria. Hundreds of years later, Fatima al-Fihri is said to have built a mosque in Fez. It grew into a famous school that is still running today.","minAge":4},{"event":"hildegard-of-bingen-writes-physica","year":1151,"label":"Hildegard of Bingen Writes Physica","emoji":"🌿","link":"About three centuries after al-Qarawiyyin was founded, in a German monastery, abbess Hildegard of Bingen drew on its herbal garden and infirmary to write Physica, on healing plants, animals and stones — recording a medicine, practised mainly by women, rarely written down.","kidsLink":"Fatima's mosque grew into a school that is still open today. Long after that, in Germany, a nun named Hildegard used plants from her garden to write a book about how to use them for healing.","minAge":4},{"event":"sor-juana-defends-women-s-right-to-learn","year":1691,"label":"Sor Juana Defends Women's Right to Learn","emoji":"✒️","link":"Hildegard had studied and written from inside her abbey. Five centuries later in colonial Mexico, the nun Sor Juana used her convent the same way — and when a bishop publicly told her to give up worldly studies for religious ones, she answered with a formal defense of women's right to learn.","kidsLink":"Hildegard wrote about plants and healing. Long after, in Mexico, a nun named Sor Juana wrote a bold defense of a woman's right to learn and study.","minAge":4},{"event":"maria-sibylla-merian-publishes-insect-metamorpho","year":1705,"label":"Maria Sibylla Merian Publishes Insect Metamorphosis","emoji":"🦋","link":"Sor Juana argued for women's learning from inside the Church, and within a few years had lost her library of thousands of books. German-Dutch artist Maria Sibylla Merian paid her own way: she sold 255 of her own paintings to fund a voyage to Suriname, and published the insect life cycles she observed there.","kidsLink":"Sor Juana fought to be allowed to study and write. Maria Sibylla Merian found her own way to study nature. She sailed to South America. There she drew how caterpillars turn into butterflies.","minAge":4},{"event":"emilie-du-chatelet-finishes-translating-newton","year":1749,"label":"Émilie du Châtelet Finishes Translating Newton","emoji":"📐","link":"Merian had paid her own way to Suriname. In France, Émilie du Châtelet worked from within elite society instead, using her mathematics and physics to produce the French translation of Newton's Principia she finished the year she died — still the standard French translation today.","kidsLink":"Merian paid her own way to study nature. In France, Émilie du Châtelet studied math and physics so well that she translated Newton's famous science book into French, the same version still used today.","minAge":7},{"event":"caroline-herschel-discovers-her-first-comet","year":1786,"label":"Caroline Herschel Discovers Her First Comet","emoji":"☄️","link":"Du Châtelet's science won her no salary. In England nearly four decades later, Caroline Herschel found her first comet in 1786, and the next year became the first woman paid a salary for scientific work, granted an annual stipend by King George III. She went on to discover eight comets.","kidsLink":"Émilie du Châtelet was never paid for her science. Caroline Herschel found eight comets in the sky and became the first woman ever paid a salary for science work.","minAge":4},{"event":"wang-zhenyi-explains-how-lunar-eclipses-happen","year":1786,"label":"Wang Zhenyi Explains How Lunar Eclipses Happen","emoji":"🌙","link":"Caroline Herschel had her brother's telescopes and a royal stipend behind her. In Qing China in those same years, Wang Zhenyi, largely self-taught in astronomy, modelled an eclipse with a round table, a hanging lamp and a round mirror, and explained lunar eclipses in terms consistent with modern astronomy.","kidsLink":"Caroline Herschel used her brother's telescope to find comets. Around the same time in China, Wang Zhenyi mostly taught herself astronomy. She used a table, a lamp and a mirror to show how lunar eclipses happen.","minAge":7},{"event":"mary-anning-finds-a-complete-ichthyosaur","year":1811,"label":"Mary Anning Finds A Complete Ichthyosaur","emoji":"🦴","link":"Wang Zhenyi largely taught herself from books. On the English coast, working-class fossil hunter Mary Anning learned from the cliffs themselves — and dug up a skeleton so important that gentlemen scientists bought her finds and wrote papers on them that often never mentioned her name.","kidsLink":"Wang Zhenyi used science to explain the moon. Mary Anning used her sharp eyes to find the skeleton of a sea reptile from long, long ago, by the sea in England. It changed how people understood ancient life.","minAge":4},{"event":"ada-lovelace-s-computing-notes","year":1843,"label":"Ada Lovelace's Computing Notes","emoji":"💻","link":"Mary Anning was shut out by class as well as sex. Ada Lovelace, a lord's daughter tutored in mathematics from childhood, faced only the second barrier; in her notes on Babbage's Analytical Engine she published what is regarded as the first algorithm meant for a machine, imagining computers doing more than arithmetic.","kidsLink":"Mary Anning had to fight hard just to be noticed for her fossil finds. Ada Lovelace had more advantages. She used her math lessons to write what many call the very first computer program.","minAge":4},{"event":"elizabeth-blackwell-earns-md","year":1849,"label":"Elizabeth Blackwell Earns MD","emoji":"🩺","link":"Ada Lovelace had published her notes in London. Six years later Elizabeth Blackwell forced a different first: turned down by school after school, she was admitted by one that let its male students vote, and they voted yes as a joke. In 1849 she became the first woman to earn a US medical degree.","kidsLink":"Ada Lovelace wrote clever ideas about machines. A few years later, Elizabeth Blackwell became the very first woman in the United States to earn a degree as a doctor.","minAge":4},{"event":"anandibai-joshi-medical-degree-1886","year":1886,"label":"Anandibai Joshi Earns Her Medical Degree","emoji":"🩺","link":"Blackwell had broken through by finding one US school willing to admit her. Decades later Anandi Gopal Joshi sailed from Calcutta to New York to study medicine in Pennsylvania — one of the first Indian women to earn a Western medical degree. Kadambini Ganguly was the first Indian woman doctor to practise.","kidsLink":"Elizabeth Blackwell was the first woman in America to earn a degree as a doctor. Years later, Anandi Joshi sailed from India to America. She trained hard. She became a doctor too.","minAge":4},{"event":"radium-1898","year":1898,"label":"The Curies discover radium","emoji":"🔬","link":"Joshi had crossed an ocean to study medicine. A dozen years later in Paris, Marie and Pierre Curie discovered two intensely radioactive new elements, polonium and radium, and coined the word 'radioactivity'.","kidsLink":"Anandi Joshi became a doctor far from home. A few years later in Paris, Marie and Pierre Curie discovered two new elements: polonium and radium.","minAge":4},{"event":"leavitt-finds-a-yardstick-for-the-universe","year":1912,"label":"Leavitt Finds a Yardstick for the Universe","emoji":"⭐","link":"The Curies' new elements reshaped physics and chemistry; measuring the universe was a separate puzzle. At the Harvard College Observatory, cataloguing the brightness of stars, Henrietta Leavitt found a fixed link between how bright certain stars are and how fast they pulse: a way to measure vast cosmic distances.","kidsLink":"Marie and Pierre Curie discovered radioactive elements. Henrietta Leavitt studied the stars. She found a trick for measuring how far away stars are.","minAge":4},{"event":"emmy-noether-theorem","year":1918,"label":"Emmy Noether links symmetry and physics","emoji":"➗","link":"Leavitt worked as one of Harvard's human 'computers', where women were not allowed to operate the telescopes. In Germany, Emmy Noether was kept out of university posts as a woman — yet in 1918 she published a theorem tying every continuous symmetry to a conservation law, now a cornerstone of modern physics.","minAge":10},{"event":"cecilia-payne-reveals-what-stars-are-made-of","year":1925,"label":"Cecilia Payne Reveals What Stars Are Made Of","emoji":"⭐","link":"Noether had to do her mathematics around the rules of German universities. Seven years later, Cecilia Payne's 1925 thesis met a different obstacle: she found stars are made mostly of hydrogen, and senior astronomers dismissed the result — until later observations proved her right.","kidsLink":"Henrietta Leavitt found a way to measure distances to stars. Years later, Cecilia Payne studied starlight and figured out that stars are made mostly of hydrogen gas.","minAge":4},{"event":"lise-meitner-nuclear-fission","year":1938,"label":"Lise Meitner Explains Nuclear Fission","emoji":"⚛️","link":"Payne's find had been doubted, then confirmed. Lise Meitner's came under harsher pressure: exiled in Sweden after fleeing Nazi Germany, she and her nephew Otto Frisch worked out that a puzzling experiment meant a uranium nucleus had split — explaining fission, though she refused to help build a bomb from it.","minAge":10},{"event":"rosalind-franklin-photo-51","year":1952,"label":"Rosalind Franklin's lab captures Photo 51","emoji":"🧬","link":"The Nobel Prize for fission went to Meitner's colleague Otto Hahn alone. Rosalind Franklin met a similar fate: in 1952 her student Raymond Gosling made 'Photo 51', a strikingly clear X-ray image of DNA, yet the 1962 Nobel Prize for DNA's structure went to three men. Franklin had died in 1958.","kidsLink":"Cecilia Payne figured out what stars are made of. Years later, a scientist working with Rosalind Franklin took a special X-ray picture that helped show DNA is shaped like a twisty ladder.","minAge":4},{"event":"marie-tharp-ocean-floor","year":1957,"label":"Marie Tharp maps the ocean floor","emoji":"🌊","link":"Franklin's photograph gave others the evidence for DNA's structure. Around the same years, geologist Marie Tharp, with Bruce Heezen, turned depth soundings into the first scientific map of the Atlantic floor, finding a rift valley along the giant mountain range down its middle — work that helped prove continents move.","kidsLink":"Rosalind Franklin's team took an X-ray picture of DNA. Marie Tharp used ocean measurements to draw the first scientific map of the Atlantic Ocean floor. It showed a giant mountain range with a crack down its middle.","minAge":4},{"event":"chien-shiung-wu-parity","year":1957,"label":"Chien-Shiung Wu overturns a law of physics","emoji":"⚛️","link":"While Tharp was still mapping the ocean floor, physicist Chien-Shiung Wu was running an experiment of her own: over the turn of 1956–57 she proved nature does not always treat left and right the same way, overturning the assumed law of parity. The theorists who predicted the result won the Nobel Prize; Wu did not.","kidsLink":"Marie Tharp mapped mountains under the ocean. Around the same time, Chien-Shiung Wu did an experiment with tiny particles. She proved that nature does not always treat left and right the same way.","minAge":4},{"event":"jane-goodall-begins-watching-chimpanzees","year":1960,"label":"Jane Goodall Begins Watching Chimpanzees","emoji":"🐒","link":"Wu had to prove her result inside a physics establishment convinced it knew the answer. Jane Goodall went into the field instead: arriving at Gombe Stream, Tanzania, in 1960 with no university degree, she watched wild chimpanzees use tools — reshaping what scientists thought made humans unique.","kidsLink":"Chien-Shiung Wu proved something surprising about tiny particles. Jane Goodall went to Tanzania and watched wild chimpanzees use tools, which surprised scientists too.","minAge":4},{"event":"rachel-carson-publishes-silent-spring","year":1962,"label":"Rachel Carson Publishes Silent Spring","emoji":"🌿","link":"Goodall had shown chimpanzees were more like us than scientists assumed. Two years later marine biologist Rachel Carson turned her own study of nature into a warning: her book Silent Spring documented the damage pesticides like DDT were doing, and helped launch the environmental movement.","kidsLink":"Jane Goodall showed that chimpanzees are a lot like us. Rachel Carson wrote a book called Silent Spring. It warned that bug-killing chemicals were hurting nature too, and it helped start the environmental movement.","minAge":7},{"event":"first-pulsar-detected","year":1967,"label":"First Pulsar Detected","emoji":"⏱️","link":"Carson had shown what patient observation of nature could reveal. Five years later a postgraduate student, Jocelyn Bell Burnell, noticed a strange, precisely repeating signal on her chart-recorder paper: the first pulsar ever detected, a fast-spinning neutron star sweeping radiation like a lighthouse.","kidsLink":"Rachel Carson wrote about protecting nature. Jocelyn Bell Burnell noticed a strange signal from space, and it turned out to be a pulsar, a fast-spinning star.","minAge":4},{"event":"vera-rubin-dark-matter","year":1970,"label":"Vera Rubin Finds Evidence for Dark Matter","emoji":"🌌","link":"Bell Burnell had found something unexpected in a radio signal. A few years later Vera Rubin found something unexpected in the motion of stars: they orbited within galaxies too fast to be held by visible matter alone — the first persuasive evidence for invisible dark matter, far outweighing what we can see.","kidsLink":"Jocelyn Bell Burnell discovered pulsars in space. Vera Rubin measured how fast stars move around in galaxies. She found signs that galaxies hold lots of invisible dark matter.","minAge":4},{"event":"tu-youyou-artemisinin","year":1972,"label":"Tu Youyou Discovers a Malaria Cure in an Old Text","emoji":"🌿","link":"Rubin had found evidence of a universe more hidden than anyone expected. Tu Youyou looked for something hidden differently: searching ancient Chinese medical texts, she found a 1,600-year-old recipe using sweet wormwood and isolated artemisinin, a compound that has saved millions of lives from malaria.","kidsLink":"Vera Rubin found signs of invisible matter in space. Tu Youyou looked in a very old medicine book and found a plant recipe that helped cure malaria.","minAge":4},{"event":"crispr-2012","year":2012,"label":"CRISPR gene editing","emoji":"✂️","link":"Tu Youyou had turned a plant compound into medicine. Four decades later, Jennifer Doudna and Emmanuelle Charpentier also borrowed from nature: they turned CRISPR, a system bacteria use to cut up the DNA of attacking viruses, into a programmable tool for editing DNA, transforming biology.","kidsLink":"Tu Youyou found a natural cure for malaria in an old book. Scientists Jennifer Doudna and Emmanuelle Charpentier found a new tool for editing DNA. It came from a system bacteria use to fight viruses.","minAge":4},{"event":"maryam-mirzakhani-wins-fields-medal","year":2014,"label":"Maryam Mirzakhani Wins Fields Medal","emoji":"🏅","link":"CRISPR had just given biologists a precise new tool to rewrite the code inside cells. Two years later mathematician Maryam Mirzakhani reached a first of a different kind: she became the first woman to win the Fields Medal, one of mathematics' highest honors, for her work on the geometry of Riemann surfaces.","kidsLink":"Scientists learned a new way to edit DNA. Maryam Mirzakhani became the first woman ever to win the Fields Medal, one of math's biggest prizes.","minAge":4}]},{"id":"first-cell-to-us","title":"From the first cell to us","emoji":"🧬","blurb":"Every living thing traces back to LUCA, a population of microbes that lived at least 3.5 billion years ago. Follow the steps (oxygen, cells with a nucleus, animals, life on land, the rise of mammals, relatives that walked upright) that led, one inheritance at a time, to people.","minAge":7,"kidsCut":true,"lens":"life","group":"earth-and-life","beats":[{"event":"luca-last-universal-common-ancestor","year":-3900000000,"label":"LUCA: the ancestor of everything alive","emoji":"🧬","link":"The story starts with LUCA because every branch of life since — plants, fungi, animals, us — descends from this ancient population of microbes. It is the single root the rest of this Journey climbs from, across at least 3.5 billion years.","kidsLink":"This Journey starts with LUCA because everything alive today comes from these tiny microbes. They are the very first branch of the family tree we're about to climb.","minAge":4},{"event":"oldest-stromatolites-pilbara","year":-3480000000,"label":"Microbe-built reefs: among the oldest fossils","emoji":"🪨","link":"Descended from LUCA's simple cells, mats of microbes in Western Australia built layered domes called stromatolites about 3.48 billion years ago — among the oldest widely accepted fossils, showing life was already thriving and leaving a mark on the rock record.","kidsLink":"LUCA's simple cells had multiplied by now. Some formed bacteria mats called stromatolites, some of the oldest fossils we know.","minAge":4},{"event":"great-oxidation-event","year":-2400000000,"label":"Great Oxidation Event fills the air with oxygen","emoji":"💨","link":"Among the descendants of microbes like those were cyanobacteria, which had been making oxygen by photosynthesis for hundreds of millions of years; around 2.4 billion years ago that oxygen finally built up in the atmosphere in the Great Oxidation Event.","kidsLink":"Some tiny microbes made oxygen as they lived. After ages of this, oxygen finally filled the air.","minAge":7},{"event":"origin-of-eukaryotes","year":-1800000000,"label":"The First Complex Cell","emoji":"🧬","link":"The Great Oxidation Event paved the way for complex life that breathes oxygen. Then came a new kind of cell, unlike anything before it: one with a nucleus to protect its DNA and internal compartments to divide up the work of living, the lineage every plant, animal and fungus descends from.","kidsLink":"Later, after oxygen filled the air, a new kind of cell appeared. It had a nucleus to keep its DNA safe. Every plant, animal and fungus comes from cells like this.","minAge":4},{"event":"first-eukaryotic-red-algae-bangiomorpha","year":-1047000000,"label":"Bangiomorpha, an early red seaweed","emoji":"🔴","link":"Eukaryotic cells went on to build bodies of many cells and to reproduce sexually: Bangiomorpha, a many-celled red alga from about a billion years ago, is the oldest known organism from a group still alive today, and its fossils hold the oldest evidence of sexual reproduction.","kidsLink":"Later, cells like these began to team up into bodies. Bangiomorpha was a many-celled red seaweed, and its fossils hold the oldest clues of new life made from two parents.","minAge":4},{"event":"snowball-earth-cryogenian","year":-700000000,"label":"Snowball Earth freezes the planet","emoji":"❄️","link":"Bangiomorpha-style many-celled life had arisen long before; then, around 700 million years ago, ice sheets may have reached the equator. The wild swings in climate and ocean chemistry that followed are linked to the rise of larger, more complex life.","kidsLink":"Many-celled life was already growing in the sea. Then ice may have covered almost the whole planet, and the big changes that followed are linked to bigger living things.","minAge":7},{"event":"sponge-biomarker-oman","year":-635000000,"label":"A Chemical Ghost of Ancient Sponges","emoji":"🧪","link":"Rocks from the Cryogenian, the age of the Snowball ice ages, hold a fatty molecule that certain sponges make in large amounts today, though some algae and other tiny organisms make it too. If it is a sponge fingerprint, animals may already have been living in those Cryogenian seas.","kidsLink":"In rocks from the ice-age seas, scientists found a fatty molecule that sponges make today. It hints that animals may have lived in those seas.","minAge":4},{"event":"avalon-explosion","year":-575000000,"label":"The Avalon explosion — an early burst of big life","emoji":"🌿","link":"Whether or not sponges came first, about 575 million years ago many-celled life grew large and complex, as frond-shaped soft-bodied organisms spread across the deep seafloor in the earliest known burst of big life.","kidsLink":"After the ice ages, many-celled life grew much bigger. Strange frond shapes spread across the deep seafloor.","minAge":4},{"event":"cambrian","year":-538800000,"label":"Cambrian explosion","emoji":"🦑","link":"After the mostly soft, frond-like forms of the Avalon explosion came a rapid burst of evolution called the Cambrian explosion, which filled the seas with complex animals: almost all of today's animal groups appeared within 13 to 25 million years.","kidsLink":"Later the sea filled up with lots of new animals of many kinds. This fast burst of new animals is called the Cambrian explosion.","minAge":4},{"event":"haikouichthys-our-first-backbone","year":-518000000,"label":"Haikouichthys — one of the first backbones","emoji":"🐟","link":"Among the flood of new animal body plans the Cambrian explosion produced was one tiny swimmer: Haikouichthys, whose skull and beginnings of a backbone make it one of the earliest known vertebrates.","kidsLink":"Among all the new Cambrian animals was a tiny swimmer. It had one of the first backbones, just starting to form.","minAge":4},{"event":"first-land-plants","year":-470000000,"label":"First plants creep onto land","emoji":"🌱","link":"While the first backboned animals swam in the sea, tiny plants much like today's liverworts were making their own leap: onto the bare land, beginning around 470 million years ago.","kidsLink":"The first backboned animals were swimming in the sea. Later, tiny plants like today's liverworts made a different leap: onto dry land.","minAge":4},{"event":"pneumodesmus-takes-the-first-breath-of-air","year":-414000000,"label":"Pneumodesmus, an early air-breather","emoji":"🐛","link":"Plants had begun spreading over the land from about 470 million years ago, and in time animals joined them there: Pneumodesmus, a tiny millipede-like creature from Scotland, has some of the oldest known breathing holes, showing it took oxygen straight from the air.","kidsLink":"Plants grew on land first. Millions of years later, tiny animals had joined them. Pneumodesmus was a little millipede-like animal that breathed air.","minAge":4},{"event":"gilboa-the-oldest-fossil-forest","year":-385000000,"label":"Gilboa, one of the oldest fossil forests","emoji":"🌳","link":"Land plants began as tiny creeping forms about 470 million years ago; by 385 million years ago some had grown into trees. Gilboa's fossil stumps in New York show a true forest, one of the oldest known.","kidsLink":"The first land plants were tiny. Much later, some grew tall into trees, like the old forest found at Gilboa in New York.","minAge":4},{"event":"tiktaalik","year":-375000000,"label":"Tiktaalik, the fish that walked","emoji":"🐟","link":"With forests like Gilboa's now growing on the land, Tiktaalik, a flat-headed fish with sturdy fins and a neck, sat right at the transition from water to land.","kidsLink":"Forests now grew on the land. Tiktaalik was a fish with strong fins and a neck. It sits right between life in water and life on land.","minAge":4},{"event":"hylonomus-first-reptile","year":-318000000,"label":"Hylonomus, long called the earliest reptile","emoji":"🦎","link":"Some 57 million years after Tiktaalik came Hylonomus, often called the earliest known reptile (though a 2025 study questions this), from the dawn of the amniotes: the group that includes reptiles, dinosaurs, birds and mammals.","kidsLink":"Long after Tiktaalik came Hylonomus. It is often called the first reptile, though a new study asks if that is true. It came from the start of a big family that grew to hold dinosaurs, birds and mammals.","minAge":4},{"event":"permian-extinction-great-dying","year":-252000000,"label":"The Great Dying: Earth's worst mass extinction","emoji":"🌋","link":"Some 66 million years after Hylonomus, massive volcanic eruptions in Siberia set off the Great Dying about 252 million years ago, Earth's most severe known mass extinction, wiping out about 81% of sea species and 70% of land vertebrate species.","kidsLink":"Millions of years after Hylonomus, giant volcanoes wiped out most life on Earth.","minAge":7},{"event":"first-dinosaurs","year":-230000000,"label":"First dinosaurs","emoji":"🦕","link":"The Great Dying cleared the stage for new groups, and later in the Triassic the first dinosaurs appeared, probably small, two-legged predators. They became the dominant land animals only after another mass extinction, 201 million years ago.","kidsLink":"After the big die-off, new animals got their chance. The first dinosaurs appeared, probably small and walking on two legs.","minAge":4},{"event":"morganucodon-first-mammal","year":-205000000,"label":"Morganucodon, one of the first mammals","emoji":"🐭","link":"The Great Dying had also cleared the stage for the first mammals. Around 205 million years ago, alongside the early dinosaurs, lived Morganucodon, one of the first mammals or a very close relative: a shrew-sized animal that was likely active at night.","kidsLink":"While early dinosaurs roamed, a tiny shrew-sized animal likely came out at night. Morganucodon was one of the first mammals, or very close to one.","minAge":4},{"event":"first-birds-archaeopteryx","year":-150000000,"label":"Archaeopteryx, long called the first bird","emoji":"🪶","link":"Morganucodon's mammal family was only beginning; meanwhile a dinosaur line produced Archaeopteryx around 150 million years ago, crow-sized, with feathers and wings but also teeth and a bony tail: a snapshot of dinosaurs becoming birds.","kidsLink":"Meanwhile, the dinosaurs kept changing. Archaeopteryx had feathers and wings, but also teeth and a bony tail. It shows how dinosaurs became birds.","minAge":4},{"event":"montsechia-ancient-underwater-flower","year":-130000000,"label":"Montsechia — an ancient flowering plant that lived underwater","emoji":"🪷","link":"While birds went on evolving from Archaeopteryx's relatives, plants had a revolution of their own: Montsechia, an Early Cretaceous water plant from Spain, appears to be the earliest known large fossil of a flowering plant.","kidsLink":"While birds kept changing, plants were changing too. Montsechia is one of the oldest flowering plants ever found, and it grew underwater.","minAge":4},{"event":"chicxulub","year":-66000000,"label":"Chicxulub impact: dinosaurs die","emoji":"☄️","link":"The age of the dinosaurs, which had seen early birds and flowering plants appear, ended when an asteroid about 10 kilometres wide struck what is now Mexico; the disaster is widely accepted as the main cause of the extinction of 75% of plant and animal species, including all non-bird dinosaurs.","kidsLink":"Then the age of the dinosaurs ended suddenly. A huge space rock hit Earth, and most kinds of living things died out, including the big dinosaurs.","minAge":7},{"event":"purgatorius-first-primate","year":-65000000,"label":"Purgatorius, an early primate after the dinosaurs","emoji":"🐒","link":"Just after the Chicxulub asteroid wiped out the non-bird dinosaurs, Purgatorius, a small tree-climbing mammal, appeared in what is now Montana around 65 million years ago: one of the earliest known primate relatives, the deep root of the monkey, ape and human branch.","kidsLink":"Soon after the big dinosaurs were gone, a small tree-climbing mammal called Purgatorius appeared. It was an early relative of monkeys, apes and us.","minAge":4},{"event":"proconsul-an-early-ape","year":-20000000,"label":"Proconsul, an early ape","emoji":"🐒","link":"After Purgatorius, the primate family spread into many branches over some 45 million years. By about 20 million years ago one of them, Proconsul, was a tailless, tree-climbing ape in the forests of East Africa.","kidsLink":"Over a very long time, Purgatorius's family grew many branches. One branch, Proconsul, was an ape with no tail that climbed trees in Africa.","minAge":4},{"event":"sahelanthropus-first-hominin","year":-7000000,"label":"Sahelanthropus ('Toumai'), an earliest hominin","emoji":"🚶","link":"Proconsul’s ape family kept branching in Africa; some 13 million years later, Sahelanthropus, nicknamed Toumai, is one of the oldest candidates for a human ancestor from around the time our branch split from chimpanzees.","kidsLink":"Proconsul’s ape family kept changing in Africa. Millions of years later, Toumai might be one of the first of our branch after it split from chimpanzees.","minAge":4},{"event":"first-stone-tools-lomekwi","year":-3300000,"label":"The oldest stone tools","emoji":"🪨","link":"Millions of years after Sahelanthropus, hominins far to the east, at Lomekwi in Kenya, were deliberately shaping the oldest stone tools ever found — about a million years before the oldest known fossils of our own genus, Homo.","kidsLink":"Long after Toumai lived, early human relatives in Kenya made something new. They made the oldest stone tools ever found.","minAge":4},{"event":"lucy-australopithecus","year":-3200000,"label":"Lucy the Australopithecus","emoji":"🦴","link":"The stone toolmakers at Lomekwi lived in East Africa barely a hundred thousand years before Lucy, an Australopithecus afarensis who shows hominins were already walking upright on two legs, even with a small, chimp-sized brain.","kidsLink":"The tool-makers lived in East Africa, not long before Lucy. Lucy shows early human relatives were already walking on two legs, even with a small brain.","minAge":4},{"event":"homo-habilis-the-handy-man","year":-2400000,"label":"Homo habilis, the \"handy man\"","emoji":"🪨","link":"Australopiths like Lucy walked upright with small brains; around 2.4 million years ago Homo habilis, one of the earliest members of our own genus, appeared in Africa with slightly larger brains and simple Oldowan stone tools.","kidsLink":"After Lucy's kind came a new group, Homo. Homo habilis had a slightly bigger brain and made simple stone tools.","minAge":4},{"event":"dmanisi-skull-5-georgia","year":-1800000,"label":"Dmanisi Skull 5 — early travellers out of Africa","emoji":"💀","link":"Early Homo such as Homo habilis lived in Africa; by 1.8 million years ago Homo erectus had walked out of the continent entirely, leaving skulls at Dmanisi in Georgia.","kidsLink":"Early Homo lived in Africa. Later, Homo erectus walked all the way out of Africa, as skulls found in Georgia show.","minAge":4},{"event":"wonderwerk-earliest-controlled-fire","year":-1000000,"label":"Wonderwerk Cave — the oldest known controlled fire","emoji":"🔥","link":"Homo erectus had spread beyond Africa; back in Africa, at Wonderwerk Cave in South Africa, burnt bone and ash at least a million years old are the earliest known evidence that human ancestors controlled fire.","kidsLink":"Homo erectus lived in many places. In a cave in South Africa, ash and burnt bone show people were keeping fire at least a million years ago.","minAge":4},{"event":"jebel-irhoud-sapiens-2","year":-315000,"label":"Our species is born","emoji":"👤","link":"Long after Homo erectus first left Africa, fossils at Jebel Irhoud in Morocco show Homo sapiens (us) living about 315,000 years ago: the earliest known remains of our own species.","kidsLink":"Long after Homo erectus first left Africa, our own kind of people lived in Morocco. Their fossils are the oldest known signs of Homo sapiens.","minAge":7},{"event":"neanderthal-interbreeding","year":-55000,"label":"Meeting the Neanderthals","emoji":"🧬","link":"Homo sapiens eventually spread out of Africa into Eurasia, where Neanderthals had long lived, and the two kinds of humans met and had children together: most people outside Africa still carry about 2% Neanderthal DNA.","kidsLink":"Homo sapiens eventually left Africa too. In Europe and Asia they met Neanderthals, and the two groups had children together.","minAge":4},{"event":"the-last-neanderthals-vanish","year":-38000,"label":"The last Neanderthals vanish","emoji":"👣","link":"Even after the two kinds of humans had met and mixed, the Neanderthals did not last as a people of their own: within a few thousand years of modern humans arriving in Europe, the last Neanderthals died out, leaving Homo sapiens the only humans on the continent.","kidsLink":"Even though they'd had children together, Neanderthals as their own people didn't last much longer. Soon after modern humans arrived, the last Neanderthals died out.","minAge":7}]},{"id":"how-we-got-around","title":"How we got around","emoji":"🛶","blurb":"For millions of years people went only as far as their feet could carry them. Then came boats, tamed animals, the wheel and the sail, and later steam, engines, wings and rockets, until a journey that once took a lifetime takes a day.","minAge":7,"kidsCut":true,"lens":"explore","group":"travel-and-messages","beats":[{"event":"laetoli-footprints-in-ash","year":-3700000,"label":"Laetoli — footprints frozen in volcanic ash","emoji":"👣","link":"Every journey humans would ever take, on foot, by boat, wheel or wing, rests on what these footprints prove: our ancestors already walked fully upright on two legs.","kidsLink":"This is where our story of travel begins: walking on two legs, long before boats or wheels.","minAge":4},{"event":"first-peopling-of-sahul","year":-65000,"label":"First Peopling Of Sahul","emoji":"👣","link":"Millions of years after Laetoli, walking had carried people across whole continents; reaching Sahul took a further leap, an ocean crossing from Sunda through Wallacea.","kidsLink":"Long after people first walked upright, some crossed the open sea to reach Sahul. That old land joined Australia and New Guinea.","minAge":4},{"event":"pesse-canoe-oldest-boat","year":-8000,"label":"The world's oldest known boat","emoji":"🛶","link":"Tens of thousands of years after the crossing to Sahul, someone hollowed a pine log in a land of marshes and lakes, and it survived: the oldest known boat in the world.","kidsLink":"The first people to reach Sahul had to cross the sea. Much later, someone made this pine-log canoe, the oldest boat ever found.","minAge":4},{"event":"donkey-domestication-ne-africa","year":-4500,"label":"The donkey is tamed in NE Africa","emoji":"🫏","link":"Water could carry people across marsh and sea; on land, herders in northeast Africa tamed the wild ass into the donkey, the tough pack animal that would carry trade across Egypt, Nubia and beyond.","kidsLink":"Boats moved people on water. On land, herders tamed the donkey, a strong animal that could carry heavy loads for them.","minAge":4},{"event":"invention-of-the-wheel","year":-3500,"label":"The wheel is put to use in Mesopotamia","emoji":"🛞","link":"Donkeys eased the load on people's backs; then a new idea set loads rolling: the turning wheel, first spun as a potter's wheel and later fitted to wagon axles in Mesopotamia and Europe.","kidsLink":"Donkeys carried loads on their backs. Then people invented something new: the wheel, first for making pots and then for wagons.","minAge":4},{"event":"the-sail","year":-3200,"label":"The sail captures the wind","emoji":"⛵","link":"Wheels set wagons rolling on land; on the Nile, Egyptians let the wind do the work, catching it in a sail to push their boats upstream while the current carried them back down.","kidsLink":"Wheels helped wagons roll on land. On the water, Egyptians found they could use the wind instead, by putting up a sail.","minAge":4},{"event":"dom2-horse-domestication-steppe","year":-2200,"label":"The horses we actually ride are tamed","emoji":"🐎","link":"Sails put the wind to work on the water; on land, on the steppe of Eastern Europe, a new line of tamed horses, whose genes may have given them stronger backs and calmer tempers, soon spread across Eurasia to carry people, pull loads and go to war.","kidsLink":"Sails used the wind to move boats. On the grasslands, people tamed the horses we still ride today, and these horses soon spread far and wide.","minAge":7},{"event":"sintashta-chariot-burials","year":-2000,"label":"Sintashta warriors are buried with the earliest known chariots","emoji":"🐎","link":"Back on the steppe, horses and wheels came together at Sintashta, where people in fortified towns buried the earliest known chariots with their warriors: spoke-wheeled and horse-drawn.","kidsLink":"Back on the grasslands, people hitched horses to carts with spoked wheels. These are the earliest chariots we know of.","minAge":7},{"event":"camels-cross-the-desert","year":-2000,"label":"Camels Cross The Desert","emoji":"🐪","link":"Horses were tamed for the grasslands; in the Arabian Peninsula people had tamed another animal for a harsher place, the dromedary camel, which could carry riders and heavy loads across the desert for days without water.","kidsLink":"Horses were tamed on the grasslands. In Arabia, people tamed the camel, which could carry people across hot deserts for days without water.","minAge":4},{"event":"austronesian-expansion","year":-1500,"label":"The Austronesian expansion, history's great sea migration","emoji":"🛶","link":"Chariots were changing travel on the Eurasian steppe, while on the far side of Asia a different kind of journey was under way by sea: Austronesian-speaking peoples from Taiwan were spreading in outrigger canoes on a migration that would in time reach from Madagascar to Easter Island.","kidsLink":"Chariots were racing across the grasslands. Later, people from Taiwan sailed canoes far out across the ocean.","minAge":4},{"event":"persian-royal-road","year":-500,"label":"The Persian Royal Road","emoji":"🛤️","link":"Canoes now carried people across oceans and camels across deserts, but an empire also needed its news to move fast: Persia rebuilt a 2,700 km highway with 111 relay stations so royal couriers could ride from Susa to Sardis in nine days.","kidsLink":"People could now cross oceans in canoes and deserts on camels. Persia built a huge road with relay stations, so messengers on fresh horses could ride it in just nine days.","minAge":4},{"event":"the-appian-way-begins","year":-312,"label":"The Appian Way Begins","emoji":"🛣️","link":"Persia built its Royal Road for its couriers; far to the west Rome began the Via Appia, a straight, durably paved road, one of the earliest and most important Roman roads, later called the 'queen of the long roads'.","kidsLink":"Persia built a great road for its messengers. Rome built one too, the Via Appia. People called it the 'queen of the long roads'.","minAge":4},{"event":"silk-road","year":-130,"label":"Silk Road opens","emoji":"🐫","link":"Persia and Rome had built great roads in the west; Han China now opened overland trade routes westward across Central Asia, and for centuries the Silk Road carried silk, spices, technologies, religions and diseases between East and West.","kidsLink":"Rome had its paved roads. Far to the east, China opened long trade routes across Asia, and silk and ideas travelled along them.","minAge":4},{"event":"the-rider-s-stirrup","year":322,"label":"The Rider's Stirrup","emoji":"🐴","link":"Roads gave riders a path; the stirrup, first reliably pictured in a Chinese tomb of 322, gave them stability in the saddle, changing mounted warfare and horse travel as it spread west across Eurasia.","kidsLink":"Roads gave travelers a path. Later, a tomb picture from China showed riding stirrups. Stirrups helped riders stay on their horses.","minAge":4},{"event":"grand-canal-609","year":609,"label":"China's Grand Canal","emoji":"🚤","link":"Nearly three centuries after the stirrups pictured in that Jin tomb, China, under the Sui dynasty, completed a great feat on water: the Grand Canal, linking the Yellow and Yangtze rivers as the longest artificial waterway on Earth.","kidsLink":"A few hundred years later, China finished a huge canal. It linked two great rivers and is the longest human-made waterway on Earth.","minAge":4},{"event":"polynesian-expansion","year":1200,"label":"Polynesians reach the far Pacific","emoji":"🌊","link":"Centuries after China's canal opened, Polynesian navigators, part of the wider Austronesian family of peoples, pushed on into the remotest Pacific, reading stars, currents and birds to reach Hawai'i, Rapa Nui and, last of all, Aotearoa.","kidsLink":"China built a canal for its boats. Centuries later, Polynesian sailors used the stars and waves to find islands far out in the Pacific.","minAge":4},{"event":"zheng-he-s-first-treasure-voyage","year":1405,"label":"Zheng He's First Treasure Voyage","emoji":"🚢","link":"Polynesians had crossed the Pacific in canoes; in 1405 Ming China sent a vast fleet of treasure ships across the Indian Ocean, reaching Southeast Asia, India, Arabia and East Africa over seven voyages.","kidsLink":"Polynesian sailors crossed the Pacific in canoes. Chinese admiral Zheng He sailed a huge fleet across the Indian Ocean.","minAge":4},{"event":"the-inca-road-network","year":1450,"label":"The Inca Road Network","emoji":"🏔️","link":"Zheng He's fleets had crossed seas; some decades later, across the Pacific, the Inca crossed forbidding mountains with Qhapaq Ñan, a road network about 40,000 km long, with rope bridges and relay runners called chasquis.","kidsLink":"Zheng He's ships crossed seas. In the Andes, the Inca built roads and rope bridges, and runners carried messages on foot.","minAge":4},{"event":"first-circumnavigation-completed","year":1522,"label":"First Circumnavigation Completed","emoji":"🌐","link":"Decades after the Inca built their roads across the Andes, the survivors of Magellan's expedition sailed home to Spain aboard the Victoria in 1522, completing the first voyage around the globe, though Magellan himself had died on the way.","kidsLink":"The Inca built roads across the Andes. Later, a ship called the Victoria sailed all the way around the world for the first time.","minAge":7},{"event":"montgolfier-balloon-1783","year":1783,"label":"First people fly in a hot-air balloon","emoji":"🎈","link":"A ship had now sailed around the globe; two and a half centuries later people made the first free flight, rising from the edge of Paris in the Montgolfier brothers' hot-air balloon.","kidsLink":"A ship had now sailed around the world. Later, two men rode a hot-air balloon made by the Montgolfier brothers. It was the first time people flew free.","minAge":4},{"event":"commercial-steamboat-service","year":1807,"label":"Commercial Steamboat Service","emoji":"🛥️","link":"Balloons had lifted people into the air; on the water Robert Fulton put a new kind of power to work, when his steamboat began regular passenger service on the Hudson River.","kidsLink":"Balloons lifted people into the sky. On rivers, Robert Fulton showed that steam power could carry passengers.","minAge":4},{"event":"stockton-and-darlington-railway","year":1825,"label":"Stockton And Darlington Railway","emoji":"🚂","link":"Fulton had proved steam could carry passengers on water; in northeast England the world's first public railway to use steam locomotives opened, carrying both coal and passengers.","kidsLink":"Steam engines had moved boats on water. In England, steam engines now pulled trains on the first public steam railway.","minAge":4},{"event":"liverpool-and-manchester-railway","year":1830,"label":"Liverpool And Manchester Railway","emoji":"🛤️","link":"Stockton and Darlington had shown steam locomotives could haul coal and passengers; five years later Liverpool and Manchester became the first inter-city railway run entirely by steam, linking two industrial cities.","kidsLink":"The first public steam railway was a start. Next, steam trains ran all the way between two cities, Liverpool and Manchester.","minAge":4},{"event":"transcontinental-railroad-1869","year":1869,"label":"US transcontinental railroad","emoji":"🚂","link":"Liverpool and Manchester had shown that steam rail could link cities; four decades later a golden spike in Utah joined rails from coast to coast, tying the United States together by train.","kidsLink":"Steam trains now ran between cities in England. Later, railroad tracks were joined all the way across the United States.","minAge":4},{"event":"suez-canal-1869","year":1869,"label":"Suez Canal opens","emoji":"🚢","link":"In the same year the rails met in Utah, a canal changed the sea routes: the Suez Canal joined the Mediterranean and Red Sea, slashing the voyage between Europe and Asia.","kidsLink":"In the same year as the railroad, workers finished a canal in Egypt. Ships could now sail a much shorter way between Europe and Asia.","minAge":4},{"event":"benz-motorwagen","year":1886,"label":"Benz's Patent-Motorwagen","emoji":"🚗","link":"Railways could now cross whole continents, but only along fixed tracks; in 1886 Karl Benz patented a vehicle free of rails altogether, a three-wheeled Motorwagen driven by its own engine, widely regarded as the first practical automobile.","kidsLink":"Trains could cross whole countries, but only on tracks. Karl Benz then built a vehicle with its own engine that did not need tracks at all, an early car.","minAge":4},{"event":"wright-flyer","year":1903,"label":"Wright brothers' first flight","emoji":"✈️","link":"Benz had put an engine on wheels to move people on the ground; seventeen years later Orville and Wilbur Wright put an engine on wings, making the first powered, controlled flight at Kitty Hawk.","kidsLink":"Benz had built a car with its own engine on the ground. The Wright brothers then built a machine with an engine that could actually fly.","minAge":4},{"event":"model-t","year":1908,"label":"Ford Model T introduced","emoji":"🚗","link":"Five years after the Wrights first flew, Ford was solving a different problem on the ground: making the automobile affordable, introducing the Model T in 1908 and later building it on moving assembly lines.","kidsLink":"The Wright brothers showed flying was possible. Around the same time, Ford made cars cheap enough for ordinary families to buy.","minAge":4},{"event":"panama-canal-1914","year":1914,"label":"Panama Canal opens","emoji":"🚢","link":"Ford was putting cars on the roads; at sea another shortcut opened in 1914 when the Panama Canal let ships pass between the Atlantic and Pacific through Central America, after decades of digging and disease.","kidsLink":"Ford made cars for families. At sea, a new canal in Panama let ships go between two oceans.","minAge":7},{"event":"first-jet-airliner","year":1952,"label":"First Jet Airliner","emoji":"🛬","link":"Since the Wright brothers' short hop, flight had come a long way; in 1952 the de Havilland Comet became the first commercial jet airliner, carrying fare-paying passengers about twice as fast as propeller airliners.","kidsLink":"Ships could now cross from ocean to ocean. In the sky, the Comet became the first jet plane for passengers, flying much faster than older planes.","minAge":4},{"event":"ideal-x-container-ship","year":1956,"label":"The box that globalised trade","emoji":"📦","link":"Jets sped up passengers; at sea, Malcom McLean loaded 58 metal containers onto the Ideal X, a simple box that slashed the cost of moving goods and helped make it possible to ship almost anything cheaply around the world.","kidsLink":"Jets carried people fast. Ships carried things in big metal boxes called containers, and the Ideal X carried 58 of them to another port.","minAge":4},{"event":"yuri-gagarin-first-human-in-space","year":1961,"label":"Yuri Gagarin: First Human In Space","emoji":"👨‍🚀","link":"People had now travelled by land, sea and air; in 1961 Soviet cosmonaut Yuri Gagarin went beyond them all, orbiting Earth once aboard Vostok 1 as the first human in space.","kidsLink":"People had travelled on land, by sea and in the air. Yuri Gagarin then flew around Earth in a spaceship, the first person in space.","minAge":4},{"event":"japan-s-bullet-train","year":1964,"label":"Japan's Bullet Train","emoji":"🚄","link":"Three years after Gagarin reached space, travel on the ground sped up too: the Tōkaidō Shinkansen opened between Tokyo and Osaka, the world's first railway built for high-speed travel, at up to 210 km/h.","kidsLink":"Yuri Gagarin had flown to space. Japan then built a very fast train, the bullet train, that went over 200 kilometers an hour.","minAge":4},{"event":"moon-landing","year":1969,"label":"Moon landing","emoji":"🌕","link":"Eight years after Gagarin first reached orbit, Apollo 11 took people further: Neil Armstrong became the first human to walk on the Moon, watched live by an estimated 600 million people.","kidsLink":"Gagarin had gone around Earth. Then Neil Armstrong went to the Moon and was the first person to walk on it.","minAge":4},{"event":"boeing-747-enters-service","year":1970,"label":"Boeing 747 enters service","emoji":"✈️","link":"A year after the Moon landing, the next change in flight came closer to home: in 1970 Pan Am put the 747, the first wide-body airliner, on its New York-London route, a jet it had asked for to cut the cost of each seat.","kidsLink":"People had walked on the Moon. Then a huge jet, the Boeing 747, began carrying many more people across the ocean for less money each.","minAge":4},{"event":"electric-cars-reach-one-in-five-sales","year":2023,"label":"Electric cars reach nearly one in five sales","emoji":"🔌","link":"Jumbo jets had been built to cut the cost of each airline seat; on the roads, the next big change was quieter: as battery prices fell, electric cars made up 18 percent of new cars sold worldwide in 2023.","kidsLink":"Big jets now carried many people for less money. On the roads, family cars changed too. By 2023 almost one in five new cars used electricity.","minAge":4}]},{"id":"how-we-sent-messages","title":"How we sent messages","emoji":"📨","blurb":"For most of history a message could travel only as fast as a runner, a horse or a pigeon. Then fire, flags, wires and radio waves made words outrun anything that moves, until today words from across the planet reach the phone in your pocket.","minAge":7,"kidsCut":true,"lens":"science","group":"travel-and-messages","beats":[{"event":"the-amarna-letters","year":-1340,"label":"The Amarna Letters","emoji":"✉️","link":"The Amarna letters open this story: a royal archive of clay tablets carrying diplomacy between the pharaoh and the rulers of Babylonia, Assyria, Mitanni, the Hittites and Canaan, proof that Bronze Age rulers already needed reliable ways to send words over distance.","kidsLink":"This story starts with the Amarna letters, clay letters sent between the pharaoh and other kings. Kings used them to talk to each other from far away.","minAge":4},{"event":"ancient-beacon-fire-relays","year":-601,"label":"Beacon fires relay warnings in China and Europe","emoji":"🔥","link":"Where the Amarna letters carried full sentences by hand, China and Europe show a different approach centuries later: shrinking a message to a simple fire or drum signal passed from tower to tower, trading detail for speed.","kidsLink":"The Amarna letters were long messages carried by hand. Later, people in China and Europe found a faster way: lighting fires or beating drums to send a quick warning instead.","minAge":7},{"event":"achaemenid-royal-couriers-angarium","year":-500,"label":"The King's tireless couriers","emoji":"🐎","link":"Beacon fires could send only simple, agreed-in-advance signals; Persia's angarium carried messages by relay, with fresh horses and riders a day's ride apart along the Royal Road speeding them some 2,700 km from Susa to Sardis in nine days.","kidsLink":"Fire signals could only send simple warnings. In Persia, riders on fresh horses passed messages along the Royal Road, a very long way in just nine days.","minAge":4},{"event":"qin-han-relay-posts-and-beacons","year":-200,"label":"China's Qin–Han relay posts and beacon lines","emoji":"🐎","link":"Centuries after Persia's royal riders, the newly unified Qin state standardized its courier relay stations under one name, You, with couriers carrying sealed documents station to station, while in Han times flags, fires and smoke still handled fast alarms that didn't need words.","kidsLink":"Later, China had its own relay system called the You. Sealed letters moved from station to station, while flags, fire and smoke still sent quick warnings.","minAge":4},{"event":"roman-cursus-publicus","year":-20,"label":"Roman Cursus Publicus","emoji":"📮","link":"As China's relay posts moved documents along its imperial highways, Rome built a similar system a world away: Augustus's cursus publicus set up posting stations along Roman roads so official news and letters could travel quickly across the empire.","kidsLink":"Far away from China, Rome built a similar system. Emperor Augustus set up relay stations along Roman roads so news could travel fast across the empire.","minAge":4},{"event":"abbasid-barid-postal-intelligence-service","year":760,"label":"The Abbasid barid carries letters and news","emoji":"🐎","link":"Rome's post served one empire; centuries later the Abbasid caliphs ran their own state courier service, the barid, which carried official letters and which al-Mansur also used to keep watch on affairs across his lands.","kidsLink":"Rome had a state post. Later, the Abbasid caliphs had one too, called the barid. Couriers carried letters and brought the caliph news.","minAge":7},{"event":"nur-ad-din-pigeon-post","year":1167,"label":"Nur ad-Din's pigeon post, Baghdad to Syria","emoji":"🕊️","link":"The barid relied on couriers; in 1167 Nur ad-Din's regular service between Baghdad and Syria used homing pigeons instead, birds that flew back to their own nests with a note tied to the leg.","kidsLink":"The barid used couriers. Nur ad-Din used pigeons instead. A note was tied to a bird's leg, and the bird flew home between Baghdad and Syria.","minAge":4},{"event":"the-yam-mongol-postal-relay-1215","year":1234,"label":"The Yam: an empire's pony express","emoji":"🐴","link":"Pigeons could carry a note only back to their own home, but ruling a huge empire, the Mongols needed a network: they built their own version of the old relay-rider idea, the Yam, with stations about 20 to 40 miles apart across their empire.","kidsLink":"Pigeons could only fly back to their own home. The Mongols needed to send messages across a huge empire, so they built the Yam, with relay stations and fresh horses all across it.","minAge":4},{"event":"the-printing-press","year":1440,"label":"The Printing Press","emoji":"🖨️","link":"The Yam moved one message at a time from rider to rider; around 1440 Gutenberg's press in Mainz copied text instead, making books quickly and cheaply, and printing reached some 270 European cities by 1500.","kidsLink":"Mongol riders carried one message at a time. Gutenberg's press could print many copies of the same words, so reading spread fast.","minAge":4},{"event":"the-inca-road-network","year":1450,"label":"The Inca Road Network","emoji":"🏔️","link":"Around the same years that printing spread in Europe, the Inca in the Andes moved messages another way: chasqui runners stationed along the Qhapaq Ñan road system relayed them on foot, an independent take on the relay idea.","kidsLink":"While printing spread in Europe, the Inca moved news a different way. Runners called chasquis passed messages along a huge road in the mountains.","minAge":4},{"event":"taxis-postal-network-europe","year":1489,"label":"The Taxis family's posts link Europe","emoji":"🐴","link":"Where the Inca chasquis and Mongol Yam served their empires, the Taxis family in Europe ran posts of their own, and from 1506 Francesco von Taxis opened the family post to public use.","kidsLink":"Earlier relay systems mostly carried messages for kings. In Europe, the Taxis family ran a mail service, and later regular people could use it too.","minAge":4},{"event":"first-printed-newspaper","year":1605,"label":"First Printed Newspaper","emoji":"📰","link":"Printing and regular posts were both established in Europe by then; in 1605 Johann Carolus put them to work in Strasbourg, publishing the Relation, a printed paper with a fresh round of news every week.","kidsLink":"By then Europe had printing presses and mail. In 1605 Johann Carolus printed the Relation, a paper with fresh news every week.","minAge":4},{"event":"west-african-talking-drums","year":1750,"label":"Talking drums relay news across West Africa","emoji":"🥁","link":"Europe's news now came as print and letters; in West Africa drummers sent news by making drums imitate speech, with each drummer passing the message on, sometimes up to about 20 miles.","kidsLink":"In Europe, news came on paper. In West Africa, drummers made drums copy speech and passed news along from drummer to drummer.","minAge":4},{"event":"chappe-s-optical-telegraph","year":1794,"label":"Chappe's Optical Telegraph","emoji":"🕯️","link":"Like the talking drums, and the beacon fires long before them, Claude Chappe's telegraph in France relayed a signal rather than an object, but with a code: a single symbol could cross the 230 km of towers from Paris to Lille in about two minutes.","kidsLink":"Drums could send signals without carrying anything. In France, Claude Chappe had a similar idea. His line of towers passed coded signs from one to the next, so messages could travel fast without a rider.","minAge":4},{"event":"cooke-wheatstone-telegraph-1837","year":1837,"label":"The first commercial telegraph","emoji":"⚡","link":"Chappe-style towers needed a clear line of sight and could not work well at night or in bad weather; in 1837 Cooke and Wheatstone patented a telegraph that sent messages along wires by electricity instead, and from 1838 it ran on the Great Western Railway, day or night.","kidsLink":"Chappe's tower signals only worked in daylight and clear weather. Cooke and Wheatstone built a telegraph that used electricity in wires instead, so messages could travel any time.","minAge":4},{"event":"the-postage-stamp","year":1840,"label":"The Postage Stamp","emoji":"📮","link":"The electric telegraph was still brand new and most people still sent news by letter; in 1840 Britain overhauled the post with the Penny Black, making a prepaid letter to anywhere in the country cost one penny.","kidsLink":"The telegraph was brand new, and most people still sent letters. In 1840, Britain made mailing a letter anywhere cost just one penny.","minAge":4},{"event":"the-pony-express-rides","year":1860,"label":"The Pony Express Rides","emoji":"🏇","link":"Britain's Penny Black made letters cheap to send; across the American West in 1860 the Pony Express showed the other aim, speed, with relay riders carrying mail about 1,900 miles in about ten days.","kidsLink":"The Penny Black made mail cheap. The Pony Express made mail fast. Riders crossed the American West in about ten days.","minAge":4},{"event":"transcontinental-telegraph-1861","year":1861,"label":"The transcontinental telegraph links the coasts","emoji":"⚡","link":"A year later telegraph crews working from east and west completed a line through Salt Lake City, so a message could cross America almost instantly instead of in ten days, and the Pony Express was suddenly obsolete.","kidsLink":"A year later, workers finished a telegraph line across America. Messages could now cross the country almost at once, so the Pony Express was not needed.","minAge":4},{"event":"transatlantic-telegraph-cable","year":1866,"label":"Transatlantic Telegraph Cable","emoji":"🌐","link":"Wires had now crossed a continent; in 1866 a durable cable laid on the Atlantic seabed between Ireland and Newfoundland carried telegraph messages between Europe and North America in minutes rather than weeks.","kidsLink":"Telegraph wires crossed a country. Then a cable under the ocean linked Ireland and Newfoundland, so messages crossed the Atlantic in minutes.","minAge":4},{"event":"australian-overland-telegraph-1872","year":1872,"label":"A wire crosses Australia's outback","emoji":"🌏","link":"With cables linking Europe and North America, news still took months to reach Australia by ship; in 1872 the Overland Telegraph from Adelaide to Darwin joined an undersea cable, cutting that to hours.","kidsLink":"The ocean cable linked Europe and North America. In 1872 a telegraph line across Australia joined the world's cables, so news arrived in hours.","minAge":4},{"event":"universal-postal-union-1874","year":1874,"label":"The Universal Postal Union Links World Mail","emoji":"📬","link":"Telegraph wires now tied distant countries together, yet a letter mailed abroad still faced a tangle of separate treaties; the 1874 Treaty of Bern replaced them with one shared postal system and one flat rate.","kidsLink":"Telegraphs now linked far places, but mailing a letter to another country was still hard. In 1874, countries agreed on one shared system.","minAge":4},{"event":"telephone","year":1876,"label":"The telephone","emoji":"☎️","link":"Telegraphs and the newly unified post both carried written words, so every message still had to be written down first; in 1876 Alexander Graham Bell's telephone let a voice itself travel down a wire, live.","kidsLink":"Telegraphs and mail could send written words, but someone still had to write everything down. The telephone let people's actual voices travel down a wire instead.","minAge":4},{"event":"marconi-s-transatlantic-signal","year":1901,"label":"Marconi's Transatlantic Signal","emoji":"📡","link":"The telephone still needed a wire strung the whole way; radio needed none, and in 1901 Guglielmo Marconi reported receiving a radio signal sent across the Atlantic, showing that wireless messages could span an ocean.","kidsLink":"The telephone needed a wire the whole way. In 1901, Marconi said he picked up a radio signal that flew through the air, with no wire at all, all the way across the ocean.","minAge":4},{"event":"first-radio-broadcast-station","year":1920,"label":"KDKA Radio Airs the Election","emoji":"📻","link":"Marconi had shown a wireless signal could reach one distant receiver; two decades later, Pittsburgh's KDKA used radio to broadcast to everyone who owned a receiver at once, an early step from point-to-point signalling to mass communication.","kidsLink":"Marconi sent a signal to just one place far away. KDKA used radio to broadcast news to anyone with a radio at the same time, reaching lots of people at once.","minAge":4},{"event":"bbc-television-service-1936","year":1936,"label":"Television Comes to Britain","emoji":"📺","link":"Radio broadcasting like KDKA's could send sound to a mass audience but no picture; in 1936 the BBC's Alexandra Palace service added moving images, launching the world's first regular high-definition television service.","kidsLink":"Radio could send sound to lots of people, but no picture. In 1936, the BBC began a regular TV service in London that sent moving pictures too.","minAge":4},{"event":"telstar-relays-live-tv","year":1962,"label":"Telstar Relays Live TV","emoji":"🛰️","link":"Early television signals could not cross an ocean; in 1962 the Telstar satellite relayed the first live TV pictures across the Atlantic, doing for moving images what the telegraph cable had done for text a century before.","kidsLink":"Early TV signals could not cross the ocean. In 1962, the Telstar satellite sent live TV pictures across the ocean for the first time, between the US and Europe.","minAge":4},{"event":"arpanet-first-message","year":1969,"label":"ARPANET First Message","emoji":"💻","link":"Telstar had let broadcasts leap oceans by satellite; ARPANET began a different kind of link, an experimental network between computers, and in 1969 researchers sent its first message from UCLA to the Stanford Research Institute, though the computer crashed after two letters.","kidsLink":"Telstar sent TV across the ocean. Next, people began linking computers together. In 1969, researchers sent the first message over a new computer network called ARPANET.","minAge":4},{"event":"email-at-symbol-1971","year":1971,"label":"Email and the @ symbol","emoji":"📧","link":"ARPANET proved computers on a network could exchange data; in 1971 Ray Tomlinson sent the first network email, picking the @ symbol to separate a person's name from the computer holding their mailbox.","kidsLink":"ARPANET showed that computers could send messages to each other. In 1971, Ray Tomlinson sent the first email over a network, and picked the @ symbol we still use today.","minAge":4},{"event":"first-mobile-phone-call","year":1973,"label":"First Handheld Mobile Phone Call","emoji":"📱","link":"Email let written messages travel over a network, while most voice calls still ran through phones fixed in place; in 1973 Motorola's Martin Cooper made the first public call from a handheld mobile phone on a New York street, a phone a caller could carry.","kidsLink":"Email could travel over computer networks, but most phones were still stuck to a wire. In 1973, Martin Cooper made the first public call from a handheld phone you could carry anywhere.","minAge":4},{"event":"tat-8-first-transatlantic-fibre-optic-cable","year":1988,"label":"TAT-8, the first fibre-optic cable under the Atlantic","emoji":"🌊","link":"Mobile phones let a caller move freely; under the Atlantic in 1988, TAT-8 became the first transatlantic fibre-optic cable, carrying 40,000 telephone circuits and filling up in eighteen months instead of the predicted ten years.","kidsLink":"Phones could now be carried around. Under the Atlantic, a new cable called TAT-8 sent calls as flashes of light through glass.","minAge":4},{"event":"world-wide-web-proposed","year":1989,"label":"World Wide Web Proposed","emoji":"🕸️","link":"TAT-8 added huge capacity between continents, yet networked computers still had no easy way to link and browse what they held; in 1989 Tim Berners-Lee at CERN proposed the Web to link documents across the internet.","kidsLink":"Cables now joined continents, but computers had no easy way to link their pages. So Tim Berners-Lee came up with the World Wide Web.","minAge":4},{"event":"first-text-message-sent","year":1992,"label":"First Text Message Sent","emoji":"💬","link":"The Web had just begun linking documents on computers, but mobile phones were still mostly for voice; in 1992 engineer Neil Papworth sent the first SMS, 'Merry Christmas', from a computer to a phone, showing a phone network could carry short written messages too.","kidsLink":"The Web linked computer pages together, but phones were still mostly for calls. In 1992, the first text message, 'Merry Christmas', showed phones could get words too.","minAge":4},{"event":"the-iphone-debuts","year":2007,"label":"The iPhone Debuts","emoji":"📲","link":"Texting had shown a phone could carry short messages, and the Web had shown a computer could browse linked information; in 2007 the iPhone combined phone, internet and a touchscreen in one pocket device, putting both in one hand.","kidsLink":"Texting let phones send short messages. The iPhone went further, putting a phone, the internet and a touchscreen all in one device you could carry in your pocket.","minAge":4},{"event":"whatsapp-launches-2009","year":2009,"label":"WhatsApp launches","emoji":"💬","link":"The iPhone put the internet in a pocket; WhatsApp, published on the App Store in May 2009, grew into an instant-messaging app after Apple added push notifications that June, letting short messages travel over the internet.","kidsLink":"The iPhone put the internet in your pocket. Then WhatsApp let people send quick messages to each other over the internet.","minAge":4},{"event":"two-thirds-humanity-online-2023","year":2023,"label":"Two-Thirds of Humanity Is Online","emoji":"🌐","link":"Apps like WhatsApp showed what a connected phone could do; by 2023, 5.4 billion people, two-thirds of humanity, were online, though 93% of people in high-income countries were connected against only 27% in low-income ones.","kidsLink":"Phones and apps helped more people get online. By 2023, two out of every three people on Earth used the internet.","minAge":4}]},{"id":"how-we-powered-the-world","title":"How we powered the world","emoji":"⚡","blurb":"From a fire kept on purpose to oxen, water wheels and windmills, then coal, steam, oil and electricity, and at last the sun and wind: how people found ever bigger sources of energy, and why the newest ones are replacing the old.","minAge":7,"kidsCut":true,"lens":"science","group":"power-and-inventions","beats":[{"event":"wonderwerk-earliest-controlled-fire","year":-1000000,"label":"Wonderwerk Cave — the oldest known controlled fire","emoji":"🔥","link":"This story starts with the earliest known energy our ancestors used on purpose: fire, kept burning deep inside a cave at least a million years ago and perhaps used for warmth and cooking, the first of every power source that follows.","kidsLink":"This story begins with fire, the oldest power we know people learned to use. Every other kind of power in this story came after it.","minAge":4},{"event":"plough-invented","year":-4000,"label":"The ox-drawn plough","emoji":"🐂","link":"Long after fire, people found a second source of power in the muscles of other animals: harnessing oxen to a plough gave farmers far more pulling power than digging sticks and hoes.","kidsLink":"After fire, people found another kind of power: animal muscle. Oxen could pull a plough and do far more work than people alone.","minAge":4},{"event":"the-sail-harnesses-the-wind","year":-3200,"label":"The sail catches the wind on the Nile","emoji":"⛵","link":"Where oxen harnessed animal muscle on land, Egyptian sailors found a power that needed no muscle at all: catching the wind in a sail to drive boats up the Nile.","kidsLink":"Oxen used animal muscle on land. Egyptian sailors found a power with no muscle needed: they caught the wind in a sail to move their boats.","minAge":4},{"event":"water-wheel","year":-200,"label":"The water wheel does the work","emoji":"💧","link":"Sails let the wind push boats; water wheels went further, letting a river's own flow turn machinery and grind grain without human or animal muscle.","kidsLink":"Sails let the wind push boats along. Water wheels went further: a flowing river could turn a wheel and grind grain all by itself.","minAge":4},{"event":"du-shi-waterwheel-bellows","year":31,"label":"A waterwheel works the furnace bellows","emoji":"⚙️","link":"About two centuries after Greek engineers put water wheels to work grinding grain, the Han Chinese engineer Du Shi used water power for a new job: working the bellows of iron furnaces, freeing smelting from human muscle too.","kidsLink":"In China, an engineer named Du Shi used a water wheel in a new way. It pumped air into iron furnaces, a job people had done by hand.","minAge":4},{"event":"persian-windmill","year":900,"label":"Persia builds early windmills","emoji":"🌬️","link":"Centuries after water wheels harnessed rivers, Persians in eastern Iran built some of the earliest known windmills, with sails spinning around an upright shaft to pump water and grind grain using wind alone.","kidsLink":"Water wheels used rivers to do work. Later, Persians built some of the first windmills, using wind itself to grind grain and pump water.","minAge":4},{"event":"song-coal-iron-industry","year":1078,"label":"Coal fuels Song China's iron boom","emoji":"⚫","link":"Far from Persia's windmills, Song China's ironworks grew so big that they stripped northern forests for charcoal; by the late 1000s ironworkers had learned to burn coke made from coal instead, putting a fossil fuel to work in place of wood.","kidsLink":"Far away in China, ironworks made so much iron that they used up forests for fuel. So ironworkers started burning coal instead of wood.","minAge":4},{"event":"weedley-windmill-1185","year":1185,"label":"Northern Europe's first recorded windmill","emoji":"🌬️","link":"Windmills reached Europe too, though no one is sure whether Persia's inspired them: the earliest certain record of one in northern Europe is at Weedley in Yorkshire in 1185.","kidsLink":"Windmills came to Europe too. In England, a windmill at Weedley was written down in 1185, the oldest one we know of there.","minAge":4},{"event":"newcomen-steam-engine-1712","year":1712,"label":"Newcomen's steam engine","emoji":"🚂","link":"Where wind and water had turned wheels, Thomas Newcomen built the first practical engine to put steam to work, a coal-hungry machine whose condensing steam made a vacuum that drove a piston and pumped water out of flooded mines.","kidsLink":"Mines kept filling up with water. Thomas Newcomen built a steam engine, powered by coal, to pump the water out. It was a brand new kind of machine.","minAge":4},{"event":"watt-s-separate-condenser","year":1769,"label":"Watt's Separate Condenser","emoji":"🔥","link":"Newcomen's engine worked but was coal-hungry; James Watt patented a separate condenser that drastically cut the fuel it burned, and his improved engines became one of the main drivers of the Industrial Revolution.","kidsLink":"Newcomen's steam engine used a lot of coal. James Watt found a clever fix that saved fuel, making steam engines far more useful.","minAge":4},{"event":"arkwright-cromford-mill-1771","year":1771,"label":"Cromford Mill, the first water-powered cotton factory","emoji":"💧","link":"Two years after Watt's patent, Richard Arkwright turned to an older power: he built Cromford Mill, driven by water from a lead-mine drain and a brook, showing that water power could run a factory day and night.","kidsLink":"James Watt had his clever idea. Two years later, Richard Arkwright used flowing water to run his big new cotton mill.","minAge":4},{"event":"volta-battery-2","year":1800,"label":"The Voltaic Pile","emoji":"🔋","link":"Separately from the steam and water driving factories, Alessandro Volta opened an entirely new source: he stacked metal discs to build the voltaic pile, the first battery able to give scientists a steady electric current.","kidsLink":"Factories used steam and water for power. But Alessandro Volta made something new. He built the first battery that gave steady electricity. Now scientists could use it for their tests.","minAge":4},{"event":"faraday-induction-1831","year":1831,"label":"Electromagnetic induction","emoji":"🧲","link":"Volta's battery gave scientists electricity to study; three decades later Michael Faraday found that moving a magnet could generate that same current directly, the principle behind electric generators and dynamos.","kidsLink":"Volta's battery let scientists study electricity. Later, Michael Faraday tried something new. He moved a magnet near a wire. Power began to flow. This idea runs almost every generator today.","minAge":4},{"event":"baku-first-oil-well-1846","year":1846,"label":"An oil well is drilled at Baku","emoji":"🛢️","link":"Faraday’s discovery pointed toward electric generators, but another source of energy was already being tapped: in 1846 a well was drilled for oil at Bibi-Heybat near Baku, using human and animal power rather than an engine.","kidsLink":"Faraday found a way to make electricity. Fifteen years later, workers near Baku drilled a well to find oil, a fuel.","minAge":4},{"event":"first-oil-well-1859","year":1859,"label":"America's first commercial oil well","emoji":"🛢️","link":"Thirteen years after the Baku well, Edwin Drake struck oil near Titusville, Pennsylvania, sparking America’s first oil boom and the wave of investment that made petroleum a major industry.","kidsLink":"Thirteen years after the well at Baku, Edwin Drake drilled a well in Pennsylvania and struck oil. It started a big rush to drill for more.","minAge":4},{"event":"otto-internal-combustion","year":1876,"label":"The four-stroke engine","emoji":"🔧","link":"Oil would soon have an engine to feed: in 1876 Nikolaus Otto's company built a practical engine that burned its fuel, at first coal gas, inside its own cylinders, the four-stroke design that led to the petrol engines in today's cars.","kidsLink":"Oil was a new fuel. Soon Nikolaus Otto's company built an engine that burned fuel inside itself. Engines like it, changed a little, now run cars on petrol made from oil.","minAge":4},{"event":"pearl-street-station","year":1882,"label":"Edison's first power station","emoji":"⚡","link":"While Otto's engine burned fuel to power single machines, Thomas Edison burned coal to drive six dynamos at Pearl Street, generating electricity for 82 customers at once from one power station.","kidsLink":"Otto's engine burned fuel to run one machine. Thomas Edison did something bigger: he burned coal to make electricity for hundreds of lamps at once.","minAge":4},{"event":"steam-turbine","year":1884,"label":"Parsons invents the steam turbine","emoji":"🌀","link":"Edison's station showed that central power plants could work; two years later Charles Parsons built the modern steam turbine, turning steam into fast, smooth rotation, still used in coal, gas and nuclear power stations.","kidsLink":"Edison's power station showed the idea could work. Two years later, Charles Parsons built the steam turbine. Turbines like it still make lots of electricity today.","minAge":4},{"event":"niagara-power-transmission","year":1896,"label":"Niagara sends power to the city","emoji":"🏞️","link":"Steam was not the only way to spin a generator: at Niagara Falls, falling water did the turning, and the plant proved its alternating current could travel all the way to the city of Buffalo.","kidsLink":"Steam could spin machines to make power. At Niagara Falls, falling water did the spinning, and sent electricity all the way to the city of Buffalo.","minAge":4},{"event":"obninsk-nuclear-power","year":1954,"label":"The first nuclear power station on the grid","emoji":"🏭","link":"Coal-fired steam and falling water had each driven power stations; nearly sixty years after Niagara, the Soviet Union tapped a wholly new source, splitting atoms at Obninsk to send nuclear power to the grid.","kidsLink":"Coal and rivers had both made electricity before. A power plant in Russia used atoms instead, and it was the first to send that power into the grid.","minAge":4},{"event":"bell-labs-unveils-the-modern-solar-cell","year":1954,"label":"Bell Labs Unveils The Modern Solar Cell","emoji":"☀️","link":"In the very same year Obninsk sent nuclear power to the grid, Bell Labs scientists unveiled a different new source: the first practical silicon solar cell, able to turn sunlight itself into usable electricity.","kidsLink":"The same year nuclear power reached the grid, other scientists made a new kind of power. It was the first real solar cell, which turns sunlight into electricity.","minAge":4},{"event":"oil-overtakes-coal-1950s","year":1955,"label":"Oil overtakes coal as world's top fuel","emoji":"🛢️","link":"Nuclear and solar power were just being invented, but the fuel actually running the world was shifting too: from the mid-1950s oil overtook coal as the world's foremost fuel.","kidsLink":"Nuclear and solar power were brand new inventions. At the same time, the world's main fuel changed too: oil became more important than coal.","minAge":4},{"event":"keeling-curve","year":1958,"label":"The Keeling Curve","emoji":"📈","link":"Burning coal and oil releases carbon dioxide; starting in 1958, Charles Keeling's measurements on Mauna Loa turned its build-up into a clear, rising graph, showing fossil fuels changing the air.","kidsLink":"Burning oil and coal lets out a gas called carbon dioxide. Starting in 1958, scientist Charles Keeling began measuring it, and his graph kept climbing higher.","minAge":4},{"event":"oil-crisis-1973","year":1973,"label":"The 1973 oil crisis","emoji":"🛢️","link":"The oil now filling the air with carbon dioxide had also become something the world could hardly do without, as 1973 showed: an Arab oil embargo quadrupled prices within months and shook economies everywhere.","kidsLink":"By now the world ran on oil. In 1973, an oil embargo made oil prices go up about four times in just a few months, and countries saw how much they needed it.","minAge":7},{"event":"tvindkraft-wind-turbine-1978","year":1978,"label":"Tvind's giant wind turbine starts turning","emoji":"🌬️","link":"The 1973 oil shock set off research in Denmark and the United States into bigger wind generators; five years later, at Tvind in Denmark, a school cooperative switched on a giant 2-megawatt wind turbine that set off serious research into wind power.","kidsLink":"After the oil crisis, people in Denmark and America began to study wind power. A few years later, a school in Denmark built a giant wind turbine.","minAge":4},{"event":"three-gorges-dam","year":2012,"label":"Three Gorges Dam","emoji":"🏞️","link":"Decades after Tvind's turbine, China brought a very different kind of renewable megaproject to full power: the Three Gorges Dam on the Yangtze, the world's largest power station, harnessing the river itself.","kidsLink":"Long after that first wind turbine in Denmark, China's Three Gorges Dam started working at full power. It is the world's biggest power station. It uses a river's flow.","minAge":4},{"event":"paris-agreement-2015","year":2015,"label":"The Paris Climate Agreement","emoji":"🌍","link":"Decades after Keeling's graph began climbing, with fossil fuels still burning despite projects like Three Gorges, nearly 200 nations agreed in the Paris Agreement of 2015 to hold global warming well below 2°C.","kidsLink":"Keeling's graph showed gas from burning fuels building up in the air. In 2015, almost every country agreed to work together to slow down global warming.","minAge":4},{"event":"renewables-overtake-coal-2025","year":2025,"label":"Renewables overtake coal worldwide","emoji":"⚡","link":"In the decade after Paris, clean power kept growing; in 2025, record growth led by solar lifted renewables to 33.8% of world electricity, edging past coal's 33.0% for the first time in a century.","kidsLink":"After nations made that promise, solar and wind power grew fast. By 2025, the world made more electricity from renewables than from coal, for the first time in 100 years.","minAge":4}]},{"id":"age-of-dinosaurs","title":"The age of the dinosaurs","emoji":"🦖","blurb":"After the Great Dying emptied the land, the dinosaurs rose to rule it for 135 million years, until an asteroid ended them all but one branch: the birds that still fly today.","minAge":7,"kidsCut":true,"lens":"life","group":"earth-and-life","beats":[{"event":"permian-extinction-great-dying","year":-252000000,"label":"The Great Dying: Earth's worst mass extinction","emoji":"🌋","link":"The story of the dinosaurs starts with catastrophe: massive Siberian volcanism caused the Great Dying, wiping out about 81% of species in the sea and 70% of land vertebrate species - opening the empty world that new reptile and mammal lineages, including the first dinosaurs later in the Triassic, would fill.","kidsLink":"This is where the dinosaur story begins. Huge volcanoes killed most living things on Earth, which left lots of empty space for new animals - like the first dinosaurs - to grow into.","minAge":7},{"event":"asilisaurus-a-dinosaur-cousin","year":-245000000,"label":"Asilisaurus, a dinosaur cousin","emoji":"🦎","link":"About seven million years after the Great Dying emptied the land, Triassic Pangaea already held Asilisaurus, a close dinosaur relative - showing, if its rocks are as old as most think, that the dinosaur family tree had sprouted early in the world the extinction had opened up.","kidsLink":"After the Great Dying cleared so much space, new animals like Asilisaurus could grow and spread. Asilisaurus was a close cousin of true dinosaurs.","minAge":4},{"event":"the-carnian-wet-spell-helps-dinosaurs","year":-233000000,"label":"The Carnian wet spell","emoji":"🌧️","link":"About twelve million years after dinosaur cousins like Asilisaurus appeared, the Carnian wet spell brought an unusually rainy climate for a while: moisture-loving plants spread, and early dinosaurs diversified during this time.","kidsLink":"Millions of years after early dinosaur cousins like Asilisaurus showed up, extra rain fell for a long time. While it was damp, plants spread and early dinosaurs grew into many new kinds.","minAge":4},{"event":"first-dinosaurs-ischigualasto","year":-231000000,"label":"Some of the first dinosaurs appear","emoji":"🦕","link":"Just after that Carnian wet spell, some of the earliest known dinosaurs appear in the rocks: the all-rounder Eoraptor and the meat-eater Herrerasaurus, living on a warm, forested floodplain along rivers in what is now Argentina.","kidsLink":"Right after that rainy time, some of the very first dinosaurs lived in what is now Argentina. Eoraptor and Herrerasaurus lived in warm forests along old rivers.","minAge":7},{"event":"first-mammals","year":-225000000,"label":"Early mammals appear","emoji":"🐭","link":"A few million years after the first dinosaurs appeared, the mammaliaforms - close relatives of the first true mammals - appeared alongside them: mostly small, shrew-like insect-eaters active at night, living in the shadow of the dinosaurs that would soon come to dominate.","kidsLink":"Not long after the first dinosaurs appeared, early mammals showed up too. But they were tiny, a bit like little mice, living in the dinosaurs' shadow.","minAge":4},{"event":"end-triassic","year":-201000000,"label":"End-Triassic extinction","emoji":"🌋","link":"While mammals stayed small, huge eruptions in the Central Atlantic magmatic province warmed the planet and acidified the oceans, 201.4 million years ago. The End-Triassic extinction ended most other groups of early archosaurs, but dinosaurs came through largely untouched and became the dominant land animals.","kidsLink":"While mammals stayed small, huge volcanoes erupted and warmed the planet. Many other reptiles died out, but dinosaurs came through and took over the land.","minAge":7},{"event":"cryolophosaurus","year":-190000000,"label":"Cryolophosaurus — the crested hunter of Antarctica","emoji":"🦖","link":"With most other early archosaurs gone after the End-Triassic extinction, dinosaurs became the dominant land animals - even in the warm, forested Antarctica of the Early Jurassic, where the crested predator Cryolophosaurus hunted.","kidsLink":"After that extinction cleared the way, dinosaurs took over the land, even in Antarctica. Back then it was warm and green, and that's where the crested hunter Cryolophosaurus lived.","minAge":7},{"event":"pangaea-breakup","year":-175000000,"label":"Pangaea breaks up","emoji":"🧭","link":"Some 15 million years after Cryolophosaurus, Pangaea began to break apart into northern Laurasia and southern Gondwana, slowly carrying continents like Antarctica toward their present positions - and by the Early Cretaceous the dinosaurs on each landmass were becoming strongly different from one another.","kidsLink":"Then the giant land began to split apart. Pieces like Antarctica, where Cryolophosaurus lived, slowly moved to where they are now. In time, the dinosaurs on each piece grew different from each other.","minAge":4},{"event":"anchiornis-the-dinosaur-whose-colours-we-know","year":-160000000,"label":"Anchiornis, the dinosaur whose colours we know","emoji":"🎨","link":"Meanwhile, in what is now China, small feathered dinosaurs were living in the Late Jurassic: Anchiornis, whose fossilized pigment sacs let scientists reconstruct almost the whole colouring of a Mesozoic dinosaur for the first time.","kidsLink":"Meanwhile, in China, lived a small dinosaur with feathers called Anchiornis. Scientists could even tell what colors its feathers were.","minAge":4},{"event":"giant-sauropods","year":-155000000,"label":"Giant sauropods roam","emoji":"🦕","link":"While Anchiornis and its kin stayed small in China, other dinosaur lines took the opposite path: Late Jurassic sauropods like Brachiosaurus and Diplodocus reached 40 tonnes or more, and sauropods include the largest animals ever to walk on land.","kidsLink":"Anchiornis stayed small. Other dinosaurs went huge instead. Sauropods like Brachiosaurus were the biggest animals ever to walk on land.","minAge":4},{"event":"first-birds-archaeopteryx","year":-150000000,"label":"Archaeopteryx, long called the first bird","emoji":"🪶","link":"In that same Late Jurassic world, another small feathered dinosaur lived in what is now Germany: Archaeopteryx, with feathered wings but still a dinosaur's teeth and bony tail - a classic snapshot of dinosaurs becoming birds.","kidsLink":"At the same time as those giant sauropods, small feathered dinosaurs kept changing too. Archaeopteryx had wings like a bird, but teeth and a tail like a dinosaur.","minAge":4},{"event":"montsechia-ancient-underwater-flower","year":-130000000,"label":"Montsechia — an ancient flowering plant that lived underwater","emoji":"🪷","link":"Twenty million years after Archaeopteryx, a very different kind of newcomer appeared in the dinosaurs' world: Montsechia, which appears to be the earliest known large fossil of a flowering plant - and it lived in water, in what is now Spain.","kidsLink":"Many years after Archaeopteryx, a brand new kind of plant showed up: the flower. Montsechia is one of the oldest flowering plants we have found, and it lived underwater.","minAge":4},{"event":"microraptor-the-four-winged-glider","year":-120000000,"label":"Microraptor, the four-winged glider","emoji":"🦅","link":"About ten million years after Montsechia, feathered dinosaurs were still diversifying: Microraptor, from Liaoning, China, could glide - and may even have flown - on four wings of glossy, iridescent black plumage.","kidsLink":"Later on, feathered dinosaurs kept changing too. Microraptor had four wings and shiny black feathers. It could glide, and maybe even fly.","minAge":4},{"event":"leaellynasaura-the-polar-dinosaur","year":-110000000,"label":"Leaellynasaura — a dinosaur of the polar dark","emoji":"🦎","link":"Far from Microraptor's China, near the South Pole, Leaellynasaura faced a very different challenge: it may have lived through months of polar winter darkness in Cretaceous Australia, feeding on low plants like ferns.","kidsLink":"Microraptor lived in China. Far away, near the South Pole, lived a dinosaur named Leaellynasaura. It may have lived through months of winter dark.","minAge":4},{"event":"argentinosaurus-the-continent-shaker","year":-106000000,"label":"Argentinosaurus — one of the heaviest ever","emoji":"🦕","link":"While Leaellynasaura lived through the polar dark, giants grew elsewhere in the south. A few million years later in Argentina, the titanosaur Argentinosaurus reached an estimated 30–35 metres and 65–80 tonnes, one of the largest land animals known.","kidsLink":"That little dinosaur lived in the cold. A few million years later, a giant lived in Argentina. It was one of the biggest land animals ever.","minAge":4},{"event":"spinosaurus","year":-99000000,"label":"Spinosaurus, the river hunter","emoji":"🐊","link":"Giant plant-eaters like Argentinosaurus were not the only way to be big. Several million years later, in the rivers of North Africa, Spinosaurus, a sail-backed predator as long as T. rex or longer, hunted fish.","kidsLink":"Argentinosaurus ate plants. Millions of years later, a huge meat-eater called Spinosaurus hunted fish in the rivers of North Africa.","minAge":7},{"event":"maiasaura-the-good-mother-lizard","year":-76000000,"label":"Maiasaura, the 'good mother lizard'","emoji":"🪹","link":"More than twenty million years after Spinosaurus, fossils in Montana revealed a softer side of dinosaur life: Maiasaura nested in vast colonies and fed its hatchlings in the nest, the first strong evidence that dinosaurs cared for their young.","kidsLink":"Long after Spinosaurus, fossils in Montana showed something sweet. Maiasaura fed her babies in the nest.","minAge":4},{"event":"protoceratops-the-nest-guardian","year":-72000000,"label":"Protoceratops — a small horned-face dinosaur","emoji":"🦏","link":"A few million years after Maiasaura, across the world in the Mongolian desert, a very different fossil captured a fiercer side of dinosaur life: Protoceratops locked in combat with a Velociraptor, the pair probably buried together by a sandstorm or a collapsing sand dune.","kidsLink":"A little after Maiasaura, a strange fossil turned up in the desert. It shows two dinosaurs fighting, probably when sand fell on them both.","minAge":7},{"event":"titanosaur-hatchery-narmada-valley","year":-70000000,"label":"Titanosaur nesting grounds of India","emoji":"🥚","link":"A couple of million years after that fight in Mongolia, on the other side of the world, titanosaurs in India left their own record of colonial nesting: 256 fossil eggs in 92 nests at Dhar alone, part of nesting sites stretching about 1,000 kilometres - one of the largest dinosaur hatcheries known.","kidsLink":"A while after that fight in Mongolia, giant titanosaurs in India laid eggs too. Scientists found more than 250 eggs close together - one of the biggest dinosaur nurseries ever found.","minAge":4},{"event":"triceratops-three-horns","year":-67000000,"label":"Triceratops, three horns and a frill","emoji":"🦏","link":"Around this time, while titanosaurs nested in India, a heavy horned plant-eater lived on the opposite side of the globe in North America: Triceratops, with its three horns and bony frill, shared its world with Tyrannosaurus rex and may have fought it off.","kidsLink":"Around this time, while those giant titanosaurs nested in India, a very different dinosaur called Triceratops lived in North America. Its three horns and bony frill may have helped it fight off T. rex.","minAge":7},{"event":"deccan-traps","year":-66200000,"label":"The Deccan Traps erupt","emoji":"🌋","link":"Triceratops and its neighbors were living on borrowed time: as the Cretaceous drew to a close, the Deccan Traps began flooding India with lava for hundreds of thousands of years, possibly straining ecosystems just as an asteroid was about to strike.","kidsLink":"While Triceratops was still alive, huge volcanoes started flooding India with lava. This may have made life harder for animals, right before a giant space rock hit.","minAge":7},{"event":"chicxulub","year":-66000000,"label":"Chicxulub impact: dinosaurs die","emoji":"☄️","link":"While the Deccan Traps were possibly already straining life, an asteroid about 10 kilometres wide struck what is now Mexico - widely accepted as the main cause of the extinction of 75% of plant and animal species, including all non-avian dinosaurs.","kidsLink":"While those volcanoes were still erupting, a giant space rock crashed into Earth. That was the end for almost all the dinosaurs.","minAge":7},{"event":"ground-birds-survive-the-impact","year":-66000000,"label":"Ground birds survive the impact","emoji":"🐦","link":"The Chicxulub impact killed every non-avian dinosaur and archaic bird groups too - but a small number of ground- and water-dwelling bird species survived, perhaps by sheltering in burrows, marshes or water, becoming the ancestors of every bird alive today.","kidsLink":"That asteroid killed almost every kind of dinosaur. But a few birds that lived on the ground or near water managed to survive, hiding in burrows or water.","minAge":7},{"event":"pantolambda-first-big-plant-eater-after-the-dinosaurs","year":-60000000,"label":"Pantolambda — a big plant-eater in the early Age of Mammals","emoji":"🦴","link":"With the non-avian dinosaurs gone, the empty world was open to the survivors: within a few million years, Pantolambda became one of the first mammals to move into the large-animal niches the dinosaurs had left empty, its babies growing inside their mother for about seven months.","kidsLink":"After most dinosaurs died out, mammals finally had room to grow. A few million years later, Pantolambda became one of the first mammals to grow big.","minAge":4},{"event":"birds-the-living-dinosaurs","year":2026,"label":"Birds: over 11,000 living dinosaurs","emoji":"🕊️","link":"The mammals that filled the post-extinction world, like Pantolambda, shared it all along with the other survivors: the descendants of the ground birds that outlived Chicxulub have since diversified into more than 11,000 living species - dinosaurs that never went extinct.","kidsLink":"Mammals like Pantolambda filled the world after the dinosaurs died. But some dinosaurs never really left - today there are more than 11,000 kinds of birds, and every one of them is a dinosaur.","minAge":4}]},{"id":"how-earth-got-its-air","title":"How Earth got the air we breathe","emoji":"🌬️","blurb":"Earth's early air was a mix of volcanic gases with almost no oxygen. Tiny microbes slowly filled the sky with oxygen, land plants pushed it higher, and today people are changing the air again.","minAge":7,"kidsCut":true,"lens":"earth","group":"earth-and-life","beats":[{"event":"hadean-first-sky-stripped","year":-4480000000,"label":"Impacts drive off Earth's first sky","emoji":"💨","link":"This Journey starts at the very beginning: before there was any air to breathe, the lightest gases of Earth's first hydrogen-rich sky were driven off by the Moon-forming collision and many large impacts, clearing the way for a new atmosphere to form.","kidsLink":"This story starts at the very start. Before Earth had any air to breathe, a giant crash and big space rocks blew away the lightest gas of its first sky. That cleared the way for a new sky to form.","minAge":4},{"event":"co2-greenhouse-atmosphere","year":-4400000000,"label":"An unbreathable, carbon-dioxide sky","emoji":"🌫️","link":"Once that first sky was driven off, gas from volcanoes, plus gases delivered by asteroids, built a new atmosphere — thick with carbon dioxide, nitrogen and water vapor, but with almost no oxygen to breathe.","kidsLink":"After the lightest gas of Earth's first sky was blown away, gas from volcanoes helped make a new one. It was thick with carbon dioxide and other gases, but had almost no oxygen.","minAge":4},{"event":"oceans-condense","year":-4400000000,"label":"Steam skies rain down the first oceans","emoji":"🌊","link":"That thick volcanic sky was loaded with water vapor. As Earth slowly cooled, the vapor formed clouds and fell as rain, pooling into the planet's first oceans.","kidsLink":"That thick early sky was full of water vapor. As Earth cooled, clouds formed and rain fell, filling the first oceans.","minAge":4},{"event":"faint-young-sun-3","year":-4000000000,"label":"The Faint Young Sun","emoji":"🌤️","link":"Those new oceans should have frozen solid under a young Sun shining only about 70% as bright as today. Instead they stayed liquid, most likely because carbon dioxide and methane thick in the air trapped extra heat.","kidsLink":"The young Sun was much dimmer than today, so the new oceans should have frozen. But thick gases in the sky probably trapped enough heat to keep the water liquid.","minAge":4},{"event":"warrawoona-microbial-mats","year":-3480000000,"label":"Warrawoona: some of the oldest possible traces of life","emoji":"🟢","link":"In the warm seas that the thick early atmosphere helped keep liquid, life may already have taken hold: Australia's Warrawoona rocks hold tiny structures that look like fossil microbes, and most scientists now think they were once alive.","kidsLink":"The warm early oceans stayed liquid thanks to thick gases in the sky. Life may already have started there. Very old rocks in Australia hold tiny shapes that look like fossil microbes.","minAge":4},{"event":"hazy-orange-methane-sky","year":-3400000000,"label":"A hazy sky full of methane","emoji":"🟠","link":"Those early microbes lived under a very different sky from ours. It held no free oxygen but plenty of methane — some of it possibly made by single-celled methane-producing microbes, adding to the warming — and sunlight may have turned some of it into a haze like Titan's, so the sky may have looked hazy, not blue.","kidsLink":"Some tiny living things may even have made methane gas. The sky had no oxygen but lots of methane. Sunlight may have turned some of it into a haze, maybe even an orange one.","minAge":4},{"event":"cyanobacteria-invent-oxygen-photosynthesis","year":-2700000000,"label":"Cyanobacteria learn to make oxygen from sunlight","emoji":"🦠","link":"Under that oxygen-free, methane-rich sky, microbial life carried on for hundreds of millions of years. By about 2.7 billion years ago one group, the cyanobacteria, was using a radical new trick: splitting water with sunlight and releasing oxygen as waste.","kidsLink":"Under that hazy sky, tiny living things kept growing for a very long time. Then one kind, called cyanobacteria, learned a new trick. They split water using sunlight and let out oxygen.","minAge":4},{"event":"banded-iron-formations-rusting-oceans","year":-2500000000,"label":"The oceans rust: banded iron formations","emoji":"🟥","link":"The oxygen cyanobacteria released did not build up in the air at first — it reacted with dissolved iron in the sea, rusting it into the red-and-grey stripes of banded iron formations on the ocean floor.","kidsLink":"The oxygen these tiny living things made did not fill the sky yet. It first reacted with iron in the sea, making red and grey striped rocks.","minAge":4},{"event":"end-of-archean","year":-2500000000,"label":"The Archean ends, oxygen on the rise","emoji":"⏳","link":"While iron rusted out of the sea, life was quietly reshaping the air. By about 2.5 billion years ago the Archean was ending, and the stage was set for oxygen to flood the air.","kidsLink":"The iron in the sea was rusting, and life was changing the air. By about 2.5 billion years ago this old age of Earth was ending, ready for oxygen to flood the sky.","minAge":4},{"event":"great-oxidation-event","year":-2400000000,"label":"Great Oxidation Event fills the air with oxygen","emoji":"💨","link":"For hundreds of millions of years, oxygen from photosynthesis was soaked up by iron and other minerals. Around 2.4 billion years ago those sinks were finally overwhelmed, and oxygen began to build up in the atmosphere.","kidsLink":"For ages, the ocean and rocks soaked up the oxygen tiny living things made. About 2.4 billion years ago, they could not soak up any more, and oxygen began to fill the air.","minAge":7},{"event":"huronian-snowball-glaciation","year":-2400000000,"label":"The Huronian glaciation — a great freeze","emoji":"🧊","link":"The same oxygen that built up during the Great Oxidation Event also destroyed much of the methane that had helped keep early Earth warm. The planet cooled into an icehouse, and at least three ice ages came and went.","kidsLink":"The oxygen that filled the air also destroyed methane gas that had kept Earth warm. Without it, the planet cooled, and at least three ice ages came and went.","minAge":7},{"event":"ozone-layer-begins","year":-2300000000,"label":"The ozone shield begins to form","emoji":"🛡️","link":"The new oxygen did more than chill the planet. As it spread into the upper atmosphere, sunlight forged some of it into ozone — a thin shield that began blocking some of the Sun's harmful ultraviolet rays.","kidsLink":"The new oxygen in the sky did more than cool the world below. High up, sunlight turned some of it into ozone, a shield against harmful rays from the Sun.","minAge":4},{"event":"canfield-sulfur-ocean","year":-1800000000,"label":"The sulfur ocean and the end of iron rust","emoji":"🌊","link":"Even with oxygen now in the air, the deep sea told a different story: by about 1.8 billion years ago it had filled with poisonous hydrogen sulfide instead, locking iron away and ending the vast banded iron formations.","kidsLink":"Even though oxygen was now in the air, the deep sea was different. It filled with a poisonous gas instead, and the rusty striped rocks stopped forming.","minAge":4},{"event":"boring-billion","year":-1400000000,"label":"The Boring Billion","emoji":"😴","link":"With the deep sea possibly staying low in oxygen and rich in sulfide, and the continents barely drifting, Earth settled into the Boring Billion — a vast stretch of climatic calm in which eukaryotic cells quietly developed tricks like multicellularity and possibly sex.","kidsLink":"With the deep sea low in oxygen and the ground barely moving, Earth had a long calm stretch called the Boring Billion. Underneath, tiny cells were quietly learning new tricks.","minAge":4},{"event":"snowball-earth-cryogenian","year":-700000000,"label":"Snowball Earth freezes the planet","emoji":"❄️","link":"The long calm of the Boring Billion gave way to violent climate swings: in the Cryogenian, glaciations so severe that ice sheets may have reached the equator turned Earth into a near-frozen snowball more than once.","kidsLink":"The long calm time ended with wild climate swings. Ice sheets may have spread all the way to the equator, turning Earth into an almost frozen snowball, more than once.","minAge":7},{"event":"neoproterozoic-oxygenation-event","year":-620000000,"label":"A second breath: oxygen rises again","emoji":"💨","link":"Around the time of the Snowball Earth glaciations, oxygen was climbing again: between about 850 and 540 million years ago, the Neoproterozoic Oxygenation Event raised it significantly in air and sea, and some scientists think this let large, oxygen-hungry creatures spread.","kidsLink":"Around the time of the Snowball Earth ice ages, oxygen in the air and sea rose a lot. Some scientists think this helped big creatures spread through the seas.","minAge":4},{"event":"cambrian","year":-538800000,"label":"Cambrian explosion","emoji":"🦑","link":"With more oxygen in the air and sea, large, oxygen-hungry creatures had begun to spread. Then came the Cambrian explosion, a rapid burst of evolution in which almost all of today's animal groups appeared within 13 to 25 million years.","kidsLink":"With more oxygen in the sea, bigger creatures had begun to spread. Soon, lots of new kinds of animals appeared.","minAge":4},{"event":"first-land-plants","year":-470000000,"label":"First plants creep onto land","emoji":"🌱","link":"While the Cambrian explosion filled the seas with animal life, the continents were still bare rock. Around 470 million years ago tiny plants much like today's liverworts made the leap onto land — the first of the land plants that would go on to transform the air.","kidsLink":"While animals filled the seas, the land was still empty and bare. Then tiny plants, like today's liverworts, began to grow there, starting plant life on land.","minAge":4},{"event":"the-earliest-wildfires-leave-charcoal","year":-430000000,"label":"The earliest known wildfires leave charcoal","emoji":"🔥","link":"As those first land plants multiplied, life on land grew plentiful enough to burn — and by the late Silurian the air itself first held enough oxygen for fire. The oldest known wildfires, about 430 million years ago, are preserved as charcoal of a giant fungus in Silurian rocks in Wales and Poland.","kidsLink":"As the first land plants spread, life on land grew thick enough to burn, and the air now held enough oxygen for fire. The oldest known wildfires left charcoal in very old rocks.","minAge":7},{"event":"devonian-forests-lift-oxygen","year":-385000000,"label":"Land plants push air oxygen near 21%","emoji":"🌳","link":"After those first fires, land plants kept spreading and diversifying. By the later Devonian, vascular plants covered the land so widely that their photosynthesis lifted atmospheric oxygen to near today's roughly 21%.","kidsLink":"After those first fires, plants on land kept spreading. They made so much oxygen that the air reached close to what we breathe today.","minAge":4},{"event":"the-air-s-oxygen-peaks","year":-305000000,"label":"The air's oxygen peaks","emoji":"💨","link":"Devonian plants had pushed oxygen close to modern levels; the vast coal swamps of the Carboniferous pushed it further still, drawing carbon dioxide from the air and lifting oxygen to highs of 25–30%, possibly about 35% — a world often linked to the era's giant insects, though the cause is still debated.","kidsLink":"Swamp forests kept making more and more oxygen, until the air held much more than it does today. This extra oxygen may be why bugs grew giant back then.","minAge":4},{"event":"end-permian-oxygen-crash","year":-252000000,"label":"Oxygen crashes after the Great Dying","emoji":"📉","link":"That oxygen-rich air did not last. The Siberian Traps eruptions that triggered the end-Permian mass extinction also devastated plant life on land, and the air itself changed: oxygen fell from around 30% to below 15%.","kidsLink":"The high-oxygen world did not last. Huge volcanic eruptions caused a mass extinction that killed off many plants, and oxygen levels crashed.","minAge":7},{"event":"priestley-isolates-oxygen","year":1774,"label":"Priestley Isolates Oxygen","emoji":"💨","link":"Oxygen had shaped Earth's air and life for over two billion years before anyone understood it as a distinct gas. In 1774 Joseph Priestley focused sunlight on mercuric oxide and released a gas far better than ordinary air for breathing and burning, an experiment that helped identify oxygen.","kidsLink":"Oxygen had shaped Earth's air for billions of years, but people were only just finding it. In 1774 Joseph Priestley used sunlight to heat a chemical and found a gas better than plain air for breathing and burning.","minAge":4},{"event":"lavoisier-oxygen-combustion","year":1783,"label":"Lavoisier weighs fire and topples phlogiston","emoji":"🔥","link":"Building on the new gas found by Priestley and by Carl Scheele, Antoine Lavoisier weighed everything before and after burning, showed that burning is a substance combining with oxygen from the air, and in 1783 attacked the old phlogiston theory of fire.","kidsLink":"After Priestley found the new gas, Antoine Lavoisier studied it carefully. He showed that burning joins things with this gas from the air, and that matter is never lost.","minAge":4},{"event":"coal-iron-industry","year":1784,"label":"Coal and iron power the new age","emoji":"⛏️","link":"Lavoisier had just shown that burning means combining with oxygen from the air, and in the same decades Britain was burning coal on a new scale to smelt iron. That coal-fired Industrial Revolution began the rise in carbon dioxide, from about 280 parts per million, that burning fossil fuels still drives today.","kidsLink":"Around the same time, Britain began burning lots of coal to melt iron. Burning coal puts carbon dioxide into the air, so people began changing the sky more and more.","minAge":4},{"event":"eunice-foote-co2-experiment","year":1856,"label":"Eunice Foote finds CO2 traps heat","emoji":"🌡️","link":"As coal burning grew, Eunice Foote turned to carbon dioxide, one of the gases of the air. In 1856 she found that carbon dioxide in sunlight grew hotter than ordinary air, an early clue to the greenhouse effect.","kidsLink":"People were burning more and more coal. In 1856 Eunice Foote studied carbon dioxide, a gas in the air. She found it trapped more heat than plain air, an early clue about gases warming the planet.","minAge":4},{"event":"tyndall-heat-trapping-gases","year":1859,"label":"Tyndall Measures Heat-Trapping Gases","emoji":"🔬","link":"Three years after Foote's experiment, John Tyndall measured the effect in the lab. He showed that carbon dioxide and water vapor absorb heat while the main gases of the air, nitrogen and oxygen, absorb very little.","kidsLink":"A few years later, John Tyndall showed that gases like carbon dioxide trap heat, while most of the air traps very little.","minAge":4},{"event":"keeling-curve","year":1958,"label":"The Keeling Curve","emoji":"📈","link":"About a century after Tyndall's lab work showed carbon dioxide traps heat, Charles Keeling began measuring it in the air on Mauna Loa in 1958. His climbing graph showed carbon dioxide from burning fossil fuels steadily building up in the atmosphere.","kidsLink":"About a hundred years after Tyndall, Charles Keeling began measuring carbon dioxide on a mountain in Hawaii in 1958. His graph showed the gas climbing higher every year.","minAge":4},{"event":"ozone-hole-1985","year":1985,"label":"The ozone hole","emoji":"🕳️","link":"The Keeling Curve had shown people changing the air on a planetary scale. In 1985 scientists found another change: a growing hole in the ozone layer over Antarctica, caused by industrial chemicals, which prompted the Montreal Protocol to help it heal.","kidsLink":"The Keeling graph showed people could change the sky. In 1985, scientists found another change: a hole in the ozone layer above Antarctica, caused by chemicals people made. Countries agreed to help fix it.","minAge":4},{"event":"co2-passes-420ppm","year":2023,"label":"CO2 passes 420 ppm, a 14-million-year high","emoji":"📈","link":"The ozone treaty showed a change people could begin to reverse, but the carbon dioxide the Keeling Curve had been tracking kept climbing. By October 2023 it passed 420 parts per million, the highest in about 14 million years, in air that is otherwise about 78% nitrogen and 21% oxygen.","kidsLink":"The ozone treaty showed people could work together to help the sky heal. But carbon dioxide kept climbing. By 2023 it reached its highest level in about 14 million years.","minAge":7}]},{"id":"human-migration","title":"The story of human migration","emoji":"👣","blurb":"Nearly two million years ago our ancestors were already living outside Africa, and by about 750 years ago people had sailed as far as Aotearoa, one of the most remote corners of the Pacific. Farming, conquest, slavery, famine, war, work and now climate have kept us moving ever since: today nearly 4 in every 100 people live outside the country they were born in.","minAge":13,"kidsCut":true,"lens":"explore","group":"travel-and-messages","layers":["migration"],"beats":[{"event":"dmanisi-hominins","year":-1800000,"label":"Early humans leave Africa","emoji":"🌍","link":"Humans have always been on the move, and the story starts before our own species. About 1.8 million years ago early Homo was living at Dmanisi in Georgia, the oldest human fossils found outside Africa. Why they left, the bones cannot tell us.","kidsLink":"Our story starts long before people like us. About 1.8 million years ago, early humans were already living outside Africa, in the country of Georgia.","minAge":7},{"event":"yuanmou-man-teeth","year":-1700000,"label":"Two teeth, among China's oldest human fossils","emoji":"🦷","link":"Early humans spread far across Asia. By around 1.7 million years ago, the date most often given, Homo erectus had reached south-western China, leaving two teeth and simple stone tools at Yuanmou among elephants, rhinos and giant hyenas.","kidsLink":"Early humans spread far across Asia. Two very old teeth show they reached China about 1.7 million years ago.","minAge":7},{"event":"jebel-irhoud-sapiens","year":-300000,"label":"Oldest known Homo sapiens fossils","emoji":"💀","link":"Long after, our own species appears. Homo sapiens fossils from Jebel Irhoud in Morocco are about 300,000 years old, and hint that early sapiens lived right across Africa, not just in the east. Every journey from here on is made by people like us.","kidsLink":"Much later, our own kind of human appeared in Africa. Bones found in Morocco show our species is about 300,000 years old.","minAge":7},{"event":"first-wave-out-of-africa","year":-98000,"label":"An Early Attempt to Leave Africa — and It Faded","emoji":"🚶","link":"Leaving Africa was not one easy step. An early wave of our species reached the Levant, where the Skhul and Qafzeh fossils date to between 120,000 and 80,000 years ago, but that population seems to have died out or gone back.","kidsLink":"Our species left Africa more than once. One early group reached the Middle East, but it seems to have died out or gone back.","minAge":7},{"event":"out-of-africa","year":-68000,"label":"The great migration out of Africa","emoji":"🚶","link":"The departure that lasted came later. Between about 70,000 and 50,000 years ago a new wave of modern humans spread out of Africa, and people living outside Africa today descend mainly from it. The next beats follow that wave into new lands.","kidsLink":"Then, between about 70,000 and 50,000 years ago, a big wave of people left Africa. Most people outside Africa today come from that journey.","minAge":4},{"event":"archaic-human-dna","year":-55000,"label":"Our hidden ancient cousins","emoji":"🧬","link":"The lands they entered were not empty. Neanderthals and Denisovans already lived there, and as our species spread it met them and had children with them. That is why most people today still carry a little of their DNA.","kidsLink":"The lands they reached already had other kinds of humans. People met them and had children with them, so most of us still carry a little of their DNA.","minAge":4},{"event":"first-australians","year":-48000,"label":"The first Australians cross the sea","emoji":"🪃","link":"Some kept moving east until the land ran out, then crossed the sea. People reached Australia at least 50,000 years ago (perhaps 65,000, a date some experts question), island-hopping over stretches of open water up to 90 km wide to the lost continent of Sahul.","kidsLink":"Some people kept going east until the land ran out. Then they crossed the sea and reached Australia at least 50,000 years ago.","minAge":7},{"event":"bacho-kiro-cave","year":-44000,"label":"Bacho Kiro — among Europe's first modern humans","emoji":"🦷","link":"Meanwhile, at the other end of the wave, people pushed north-west into Europe. In a Bulgarian cave, teeth and bone about 46,000 years old are among Europe's first modern humans, and pierced animal teeth found there are its oldest known jewellery.","kidsLink":"Other people went north-west into Europe. In a cave in Bulgaria they left teeth, bones and Europe's oldest known jewellery.","minAge":7},{"event":"tianyuan-man","year":-38000,"label":"Tianyuan Man — an early East Asian, and a fish-eater","emoji":"🎣","link":"The same spread reached the far east of Asia. Near Beijing, 40,000-year-old Tianyuan Man ate a lot of freshwater fish, and his DNA links him to today's East Asians and to Native Americans, a clue to where the journey led next.","kidsLink":"Others reached East Asia. Near Beijing, the bones of a man who lived 40,000 years ago show he ate a lot of fish.","minAge":7},{"event":"yana-rhinoceros-horn-site","year":-30000,"label":"Yana — humans inside the Arctic Circle","emoji":"🥶","link":"People learned to live in the coldest lands yet. By a Siberian river north of the Arctic Circle, 32,000 years ago, they hunted mammoth, bison and reindeer in the Ice Age Arctic, in the far north-east of Asia that leads towards America.","kidsLink":"People learned to live in very cold places too. Far north in icy Siberia, they hunted mammoths and reindeer and made beads.","minAge":7},{"event":"white-sands-footprints-2","year":-20000,"label":"Footprints Frozen in an Ancient Lakebed","emoji":"👣","link":"In the Ice Age, low seas left a land bridge, Beringia, joining Asia to America, and people found their way into the Americas, over it or along its coasts. At White Sands in New Mexico, a widely cited study dated footprints of adults and children to 23,000–21,000 years ago, though scientists still debate the dates.","kidsLink":"In the Ice Age the seas were lower, and people could walk from Asia to America. In New Mexico, footprints of grown-ups and children may be over 21,000 years old.","minAge":4},{"event":"monte-verde-settlement","year":-12500,"label":"Monte Verde Settlement","emoji":"🏕️","link":"Once in the Americas, people spread far. By over 14,000 years ago, a date most archaeologists accept though some still question it, they lived at Monte Verde in southern Chile, challenging the idea that Clovis hunters were the first Americans.","kidsLink":"People spread all the way down the Americas. In southern Chile they were living over 14,000 years ago, though some experts still question the date.","minAge":4},{"event":"beringia-land-bridge-drowned","year":-9000,"label":"The Bering land bridge sinks beneath the sea","emoji":"🧊","link":"Then the climate that had opened the road closed it. As the Ice Age ended, meltwater raised the oceans, and by about 11,000 years ago the sea had drowned the grassy plain of Beringia, cutting the Americas off from Asia by water.","kidsLink":"Then the Ice Age ended and melting ice made the seas rise. The land between Asia and America was flooded, and the two were cut apart.","minAge":7},{"event":"anatolian-farmers-move-into-europe","year":-7000,"label":"Farmers from Anatolia move into Europe","emoji":"🌾","link":"After the ice, a new way of life set people moving: farming. From around 7000 BCE farming families from Anatolia moved into Europe with wheat and livestock. Ancient DNA shows people, not just ideas, moved: in the Balkans their ancestry replaced about 98% of the local hunter-gatherers' gene pool.","kidsLink":"After the ice melted, a new way of life spread: farming. About 9,000 years ago, farming families from today's Turkey moved into Europe with wheat and animals.","minAge":7},{"event":"bantu-expansion-begins","year":-3000,"label":"Bantu-speaking farmers begin their long migration","emoji":"🌍","link":"In Africa, too, farmers were on the move. From the borderlands of today's Nigeria and Cameroon, Bantu-speaking communities spread over thousands of years, carrying farming, ironworking and their languages across most of sub-Saharan Africa.","kidsLink":"Farming families in Africa moved too. People speaking Bantu languages spread slowly across much of Africa over thousands of years.","minAge":4},{"event":"yamnaya-indo-european-expansion","year":-3000,"label":"The Yamnaya ride out — and likely carry Indo-European speech across Eurasia","emoji":"🐂","link":"Meanwhile, far to the north-east, herders were on the move across the Pontic-Caspian steppe. Wagon-riding Yamnaya herders spread out in a vast migration that, most scholars think, carried the ancestry and Indo-European languages of much of Europe and Asia.","kidsLink":"Around the same time, herders with wagons were moving across the grassy steppe. They probably spread languages that grew into English and Hindi.","minAge":4},{"event":"austronesian-expansion-begins","year":-3000,"label":"Austronesian Expansion Begins","emoji":"🛶","link":"And in the same age, on the far side of Asia, the sea opened the way. From Taiwan, seafaring Austronesians spread through island Southeast Asia in outrigger canoes, carrying pottery, pigs and crops, the start of a spread that would reach across the Pacific.","kidsLink":"At the same time, other people took to the sea. Sailors from Taiwan set off in canoes with pigs, pottery and crops.","minAge":4},{"event":"tonga-samoa-settled","year":-900,"label":"Lapita voyagers settle Tonga and Samoa","emoji":"🏝️","link":"The canoes kept going east. By around 900 BCE Lapita voyagers had reached Tonga and Samoa, and there the ancestors of the Polynesians stayed for well over a thousand years before the next great push east.","kidsLink":"Their canoes went farther and farther. Almost 3,000 years ago, sailors reached Tonga and Samoa in the Pacific, and stayed there a long time.","minAge":4},{"event":"huns-arrive-in-europe","year":375,"label":"The Huns burst out of the eastern steppe","emoji":"🐎","link":"Back on the steppe the Yamnaya had left, new riders came west, and this time fear moved people. Around 375 CE the Huns shattered the Alans and Goths; thousands of Goths fled across the Danube into the Roman Empire, helping set off the great migrations of the age.","minAge":10},{"event":"madagascar-austronesian","year":500,"label":"Sailors reach Madagascar from Asia","emoji":"🛶","link":"Meanwhile, the Austronesian sailing tradition was reaching west as well as east. Around 500 CE many of Madagascar's first settlers sailed thousands of kilometres from southern Borneo, and East Africans came later, which is why Malagasy is related to languages of Indonesia.","kidsLink":"While some sailors crossed the Pacific, others sailed the other way. Many of the first people on Madagascar came across the ocean from far-off Asia.","minAge":4},{"event":"the-arab-conquest-of-egypt","year":641,"label":"The Arab conquest of Egypt","emoji":"🏺","link":"At the other end of Africa, conquest was moving people. Amr ibn al-As led an Arab army into Byzantine Egypt and took Alexandria; his camp beside the old fortress of Babylon became Fustat, 'the tent', and grew into the heart of Egypt.","minAge":10},{"event":"the-zanj-rebellion","year":869,"label":"The Zanj Rebellion","emoji":"⛓️","link":"Not everyone moved by choice. Many Africans were brought to southern Iraq through the Indian Ocean slave trade to labour on its plantations and salt flats. In 869 enslaved and free Africans rose in the Zanj Rebellion, seizing cities including Basra and defying the Abbasid state until 883.","minAge":10},{"event":"settlement-of-iceland","year":874,"label":"Settlement Of Iceland","emoji":"🇮🇸","link":"Meanwhile, in the far north, sailors were claiming new land. Around 874 the Norwegian Ingólfr Arnarson sailed to Iceland meaning to settle it; within decades settlers had claimed the whole island, many of them, medieval writers said, escaping the rule of King Harald of Norway.","kidsLink":"Far to the north, other sailors found a new island too. People from Norway sailed to Iceland to build farms, and many more families soon followed.","minAge":4},{"event":"thule-culture-expansion","year":1000,"label":"The Thule sweep across the Arctic","emoji":"🛶","link":"Across the top of the world, people were moving the other way. From coastal Alaska the Thule, ancestors of today's Inuit, spread east with dog sleds, skin boats and harpoons, hunting whales, replacing the older Dorset people and reaching Greenland by the 1200s.","kidsLink":"Far across the icy north, another people were on the move. The Thule, the ancestors of today's Inuit, travelled east from Alaska with dog sleds and skin boats.","minAge":7},{"event":"manzikert-1071","year":1071,"label":"Battle of Manzikert","emoji":"🏹","link":"In the Middle East, conquest again opened a land to settlers. In 1071 Seljuk Turks crushed a Byzantine army at Manzikert, opening Anatolia, where Europe's first farmers had set out some 8,000 years before, to Turkish settlement.","minAge":10},{"event":"polynesian-expansion","year":1200,"label":"Polynesians reach the far Pacific","emoji":"🌊","link":"Meanwhile the long Pacific pause ended. From the islands around Tonga and Samoa, Polynesian navigators reading stars, currents, clouds and birds sailed thousands of kilometres to Hawai'i, Rapa Nui and finally Aotearoa, the most remote corners of the Pacific.","kidsLink":"Meanwhile, in the warm Pacific, the sailors of Tonga and Samoa set off again. They followed the stars and the birds to far islands like Hawaiʻi.","minAge":4},{"event":"wairau-bar-first-settlers-aotearoa","year":1300,"label":"The first settlers camp at Te Pokohiwi","emoji":"⛵","link":"Aotearoa was the last of those far lands. At Wairau Bar, a village of the late 1200s and early 1300s, chemical signatures in the bones and teeth of some of those buried suggest they grew up far away, perhaps founding voyagers from tropical East Polynesia.","kidsLink":"One of their last stops was New Zealand. Clues in old bones at Wairau Bar suggest some of its first people had sailed there from warm islands far away.","minAge":7},{"event":"romani-recorded-on-crete-1322","year":1322,"label":"Romani travellers are recorded on Crete","emoji":"🧭","link":"Around the same time, a slower journey was crossing land. One 2012 study found that the Romani's ancestors left north-western India about 1,500 years ago and reached the Balkans about 900 years ago; in 1322 an Irish friar met Romani migrants on Crete.","kidsLink":"Far away, another people had been on a long, slow journey. The ancestors of the Romani left India long ago, and in 1322 a traveller met Romani people on the island of Crete.","minAge":4},{"event":"columbus-reaches-americas","year":1492,"label":"Columbus reaches the Americas","emoji":"🚢","link":"Since Beringia drowned, the ocean had kept the Americas largely apart. In 1492 Columbus, sailing west for Spain, landed on an island its people called Guanahaní, opening the way for Europeans to settle lands whose peoples had lived there for well over 10,000 years.","kidsLink":"For thousands of years the sea kept the Americas mostly apart. Then in 1492 Columbus sailed across the ocean and reached islands where people already lived.","minAge":4},{"event":"smallpox-hispaniola","year":1518,"label":"Smallpox devastates the Americas","emoji":"🦠","link":"The newcomers carried more than themselves. From about 1518, beginning with smallpox on Hispaniola, waves of Old World disease rapidly and greatly reduced Indigenous populations across the Americas, who were highly vulnerable to it.","minAge":10},{"event":"the-middle-passage","year":1640,"label":"The Middle Passage across the Atlantic","emoji":"⛓️","link":"The Atlantic crossing Columbus opened also became a route for moving people by force. Captive Africans were packed below deck for weeks or months on the Middle Passage; about one in seven died at sea, and an estimated 9.4 to 12.6 million people were carried to the Americas.","minAge":13},{"event":"first-fleet-arrives-at-sydney","year":1788,"label":"First Fleet Arrives At Sydney","emoji":"⚓","link":"Forced journeys took other forms too. In 1788 Britain's First Fleet landed convicts, with marines, officials and a few free settlers, at Sydney Cove, founding a penal colony and beginning British colonisation of a land people had reached at least 50,000 years before.","kidsLink":"After Columbus, ships carried many people across the oceans, and not all of them chose to go. In 1788 British ships brought convicts to Australia, where people had lived for at least 50,000 years.","minAge":4},{"event":"indentured-workers-reach-mauritius-1834","year":1834,"label":"Indian indentured workers reach Mauritius","emoji":"🚢","link":"When slavery was abolished in Britain's colonies in 1834, Britain looked for new plantation workers, and that year the first indentured labourers, bound by contract, began arriving in Mauritius from India. By 1923 nearly half a million Indians had come; about 68% of Mauritians today have Indian ancestry.","minAge":10},{"event":"irish-famine-1845","year":1845,"label":"The Great Irish Famine","emoji":"🥔","link":"Meanwhile, hunger drove people from Europe. From 1845 a potato blight brought famine to Ireland: about a million people died, and over a million more emigrated.","minAge":10},{"event":"chuang-guandong-farmers-pour-into-manchuria","year":1860,"label":"Chuang Guandong: farmers pour into Manchuria","emoji":"🧳","link":"In Asia, poverty and newly opened land set millions moving. Once Qing officials proposed opening Manchuria, officially closed to Han settlers for two centuries, poor farmers from Shandong and Zhili streamed north: an estimated 25.4 million arrived in 1891–1942, and about 8.7 million stayed.","kidsLink":"In the 1800s many more people moved, some because of hunger and some to find land. In China, millions of farmers went north to farm new land in Manchuria.","minAge":7},{"event":"mass-migration-19th-century","year":1880,"label":"The age of mass migration","emoji":"🧳","link":"At the other end of Eurasia, the same search for land and work sent Europeans across the ocean. Some 60 million left Europe between 1815 and 1930, most for the Americas, carried by faster, safer ships: one of the largest migrations in human history.","kidsLink":"At the same time, millions of people in Europe went looking for land and work too. Most of them sailed across the ocean to the Americas.","minAge":4},{"event":"great-migration-six-million-head-north","year":1916,"label":"The Great Migration: six million head north","emoji":"🚂","link":"People also moved within a country. From 1910 to 1970 about six million Black Americans left the rural South for cities of the North, Midwest and West, escaping Jim Crow segregation and seeking work; about 400,000 left in 1916–1918 alone to fill wartime jobs.","minAge":10},{"event":"displaced-persons-europe-1945","year":1945,"label":"Europe's 'displaced persons' after the war","emoji":"🧳","link":"Then a second world war uprooted people by the tens of millions. When it ended, at least 40 million people in Europe had been driven from their home countries; over six million were sent home by the end of 1945, but more than a million feared persecution and lived for years in camps.","minAge":10},{"event":"indian-independence-partition-1947","year":1947,"label":"Indian independence and Partition","emoji":"🇮🇳","link":"Two years later, a new border moved people too. When British India was divided into India and Pakistan in August 1947, an estimated 12 to 20 million people were uprooted amid terrible violence; estimates of the dead range from 200,000 to 2 million.","minAge":10},{"event":"israel-founding-nakba-1948","year":1948,"label":"The founding of Israel and the Nakba","emoji":"🏳️","link":"A year later a new state was born, and people moved both ways. Israel was declared in May 1948, soon after the Holocaust. In the 1948 war about 700,000 Palestinian Arabs fled or were expelled, the Nakba; in the next 3½ years about 688,000 Jewish immigrants came, mainly from Europe and the Arab and Muslim world.","minAge":10},{"event":"empire-windrush-docks-at-tilbury-1948","year":1948,"label":"Empire Windrush docks at Tilbury","emoji":"🚢","link":"The same year, a different voyage. On 21 June 1948 the Empire Windrush docked near London; 802 of its 1,027 passengers gave a Caribbean country as their last home. That year's British Nationality Act let people of Britain's colonies settle in the UK; Caribbean migrants who came until 1973 are the Windrush generation.","kidsLink":"In the 1900s people kept moving, some to find work and some to escape wars. In 1948 a ship called the Empire Windrush brought hundreds of people from the Caribbean to new homes in Britain.","minAge":7},{"event":"refugee-convention-1951","year":1951,"label":"The Refugee Convention and a rule no state may opt out of","emoji":"🛂","link":"The Second World War's millions of uprooted people pushed the world to write rules. In 1951 the UN Refugee Convention said no state may send a refugee back to face persecution, but at first it covered only people uprooted by events before 1951, and, if a state chose, only in Europe.","minAge":10},{"event":"china-villagers-move-to-the-cities","year":1978,"label":"China's villagers move to the cities","emoji":"🏙️","link":"Some of history's biggest moves never cross a border. From 1978 China's reforms loosened the rules tying farmers to their villages: an estimated 174 million people moved from countryside to city by 1999, and by 2015 China counted 277.5 million migrant workers.","kidsLink":"Some big moves happen inside one country. After 1978, millions of people in China left their villages to work in cities.","minAge":7},{"event":"un-counts-a-mostly-urban-world-2007","year":2007,"label":"The UN counts a mostly urban world","emoji":"🏙️","link":"China's move was part of a worldwide one, from farms to towns and cities. By the UN's count, 2007 was the year more than half of humanity lived in urban areas, up from about 15% around 1900, though on a newer yardstick the world was mostly urban by the 1950s.","kidsLink":"All over the world, people were moving from farms to towns and cities. By 2007, the UN counted more people living in cities than in the countryside.","minAge":4},{"event":"falepili-union-tuvalu-australia","year":2023,"label":"Tuvalu and Australia sign the Falepili Union","emoji":"🌊","link":"The force that drowned Beringia is back: rising seas. In 2023 Tuvalu and Australia signed the Falepili Union, letting up to 280 Tuvaluans a year move to Australia and recognising that Tuvalu stays a state even if the sea takes its land.","kidsLink":"Long ago, the sea rose and covered the land between Asia and America. Now the sea is rising again around the small islands of Tuvalu. So Australia will let some people from Tuvalu move there.","minAge":4},{"event":"forced-displacement-123-million-2024","year":2024,"label":"123 million people forced from home","emoji":"⛺","link":"Alongside the sea, the old forces of war and persecution still drive people from home. By the end of 2024 at least 123.2 million people, one in every 67 on Earth, had been forced from home, most of them (73.5 million) within their own countries; 13.5 million were Syrians.","minAge":10},{"event":"international-migrants-304-million-2024","year":2024,"label":"304 million people live abroad","emoji":"🌍","link":"Forced flight is only part of today's picture. In 2024 the UN counted 304 million people living outside the country they were born in, nearly twice as many as in 1990, yet still only 3.7% of humanity. The journey that began at Dmanisi goes on.","kidsLink":"People are still on the move today, for work, to be safe, and for many other reasons. In 2024, about 304 million people lived in a country where they were not born.","minAge":4}]},{"id":"the-story-of-numbers","title":"The story of numbers","emoji":"🔢","blurb":"From notches cut in a bone to machines that calculate faster than thought: how people in Africa, Mesopotamia, India, China, the Islamic world, the Americas and Europe each added a piece, place value, zero, algebra, calculus, until numbers could run a computer.","minAge":4,"kidsCut":true,"lens":"science","group":"people-and-ideas","beats":[{"event":"lebombo-bone","year":-40500,"label":"The Lebombo Bone","emoji":"🦴","link":"The story starts with one of the oldest hints we have: a row of notches cut into a bone in southern Africa. It may have been a tally stick, long before any numbers were written down.","kidsLink":"Our story starts with a bone with notches cut in it. It may have been used to count.","minAge":4},{"event":"ishango-bone","year":-18000,"label":"The Ishango Bone","emoji":"🦴","link":"Roughly twenty thousand years later, another carved bone turns up in central Africa, this time with notches in three careful columns. Many think it was also a tally, so counting with marks was no one-off.","kidsLink":"Many years later, people in Africa carved another bone with rows of notches. It was probably for counting too.","minAge":4},{"event":"clay-tokens-mesopotamia","year":-8000,"label":"Clay tokens: early accounting","emoji":"🧮","link":"Counting moves from notches to objects. Farmers in the Near East used small clay tokens to stand for their goods, and many scholars think these counters are where the first written number signs came from.","kidsLink":"Later, farmers used little clay tokens to count their goods. Each token stood for something they owned.","minAge":4},{"event":"sumerian-base-60","year":-3000,"label":"Sumer counts in base-60","emoji":"🔢","link":"Those counting habits grew into numbers written on clay tablets. The Sumerians pressed their signs into the clay and built them around 60, a choice we still live with in minutes and degrees.","kidsLink":"Next, the Sumerians pressed numbers into clay tablets. They counted in sixties, like the 60 minutes in an hour.","minAge":4},{"event":"egyptian-hieroglyphic-numerals","year":-3000,"label":"Egypt writes numbers in tens","emoji":"🔢","link":"At about the same time, Egypt found a different answer. Instead of base 60, scribes used a sign for each power of ten and repeated it, with no place value and no zero.","kidsLink":"At about the same time, Egypt had its own way. They used a picture sign for 1, 10, 100 and more.","minAge":4},{"event":"babylon-first-mathematics","year":-1800,"label":"Babylonians count in sixties","emoji":"🔢","link":"Back in Mesopotamia, Babylonian scribes used the base-60 system for real mathematics. Where Egypt repeated signs, their number's value depended on where each digit stood.","kidsLink":"In Babylon, scribes used the base-sixty system to do clever math. A digit's place changed what it meant.","minAge":4},{"event":"rhind-mathematical-papyrus-2","year":-1550,"label":"The Rhind Papyrus teaches Egyptian maths","emoji":"🔢","link":"Egyptian arithmetic also grew into a trained craft. The Rhind Papyrus is a scribe's textbook of over 80 problems on fractions and areas, showing sums being done for building and sharing grain.","kidsLink":"Egypt had math books too. A scribe copied a scroll of problems about fractions and shapes.","minAge":4},{"event":"chinese-mathematicians-compute-with-rods-on-the","year":-300,"label":"Chinese Mathematicians Compute With Rods On The Ground","emoji":"🥢","link":"China developed its own counting tool. Rods laid out in a grid worked as a place-value system, with colours for positive and negative numbers and an empty space where a digit was missing.","kidsLink":"In China, people counted by laying rods in a grid. Black and red rods showed different kinds of numbers.","minAge":4},{"event":"euclid-s-elements","year":-300,"label":"Euclid's Elements","emoji":"📐","link":"Around the same century in Alexandria, Euclid took maths in a new direction. Instead of methods for sums, the Elements built geometry step by step from axioms and proofs.","kidsLink":"Around then, Euclid wrote a book that explained shapes step by step. It showed how to prove that something is true.","minAge":4},{"event":"babylonian-scribes-mark-an-empty-place-with-a-sy","year":-300,"label":"Babylonian Scribes Mark An Empty Place With A Symbol","emoji":"🕳️","link":"Back in Babylon, a place-value system needed a way to show an empty place. Scribes added a mark so 302 differed from 32, though it was only a placeholder and not yet a number you could calculate with.","kidsLink":"Babylon's scribes had a problem with empty spots in numbers. They added a mark so 302 did not look like 32.","minAge":4},{"event":"maya-long-count-zero","year":-36,"label":"Mesoamerica's Zero","emoji":"🐚","link":"Babylon was not alone in needing a sign for an empty place. Far across the world, Mesoamerica's Long Count calendar only works with a symbol for nothing, and a monument at Chiapa de Corzo carries the oldest known Long Count date, from 36 BCE.","kidsLink":"Far away in Mexico, people also needed a sign for nothing. A stone from 36 BCE has a date in their calendar, which needed a zero.","minAge":4},{"event":"nine-chapters-compiled","year":50,"label":"The Nine Chapters reach their final form","emoji":"🀄","link":"China also worked with nothing: on its counting rods a blank space stood for zero. In the 1st century CE The Nine Chapters reached its final form, solving sets of linear equations together and giving rules for negative numbers, such as subtracting a positive number from zero to make a negative one.","kidsLink":"In China, an empty space on the counting board meant zero. A math book called Nine Chapters was finished. It had rules for numbers below zero.","minAge":4},{"event":"brahmagupta-zero","year":628,"label":"The rules of zero","emoji":"0️⃣","link":"In India, zero went beyond a blank or a placeholder. Brahmagupta's book of 628 gave rules for calculating with zero and with negative numbers, treating zero as a number in its own right.","kidsLink":"In India, Brahmagupta wrote rules for zero and for numbers below zero. He used zero as a real number, not just an empty spot.","minAge":4},{"event":"al-khwarizmi-algebra-820","year":820,"label":"Al-Khwarizmi & algebra","emoji":"📐","link":"Two centuries later in Baghdad, al-Khwarizmi wrote the founding text of algebra. He also wrote a book on calculating with Hindu numerals, which spread the Hindu-Arabic numerals through the Middle East and Europe.","kidsLink":"Next, a scholar in Baghdad wrote the book that founded algebra. His name gave us the word algorithm.","minAge":4},{"event":"gwalior-temple-of-zero-inscription","year":876,"label":"A temple wall carves a zero in stone","emoji":"0️⃣","link":"Back in India, zero appears in everyday life. A temple inscription from 876 cuts round zeros into stone in the numbers 270 and 50, described as the earliest known stone inscription to use that zero.","kidsLink":"Back in India, a temple wall has numbers with round zeros carved in stone. It is dated 876.","minAge":4},{"event":"fibonacci-liber-abaci","year":1202,"label":"Fibonacci brings 0-9 to Europe","emoji":"🔟","link":"The Hindu-Arabic digits then travelled to Europe. In 1202 Fibonacci showed in Liber Abaci that 0 to 9 made sums far easier than Roman numerals.","kidsLink":"Then the numbers 0 to 9 came to Europe. Fibonacci showed that they were easier than Roman numerals.","minAge":4},{"event":"madhava-calculus","year":1400,"label":"Madhava's Infinite Series","emoji":"➗","link":"Meanwhile in Kerala, India, Madhava wrote infinite series for pi, sine and cosine. They anticipated ideas of calculus centuries before James Gregory reached a similar series in Europe in 1667.","kidsLink":"In India, Madhava found number patterns that give pi very closely. Europeans found similar ones much later.","minAge":4},{"event":"qhapaq-nan-quipu","year":1450,"label":"Inca roads and the knotted quipu","emoji":"🪢","link":"In the Andes, the Inca kept numbers without writing. Officials recorded counts on quipu, knotted coloured cords, so number records took yet another form beside clay, rods and ink.","kidsLink":"In South America, the Inca had no known writing. They kept counts with knots tied in strings called quipu.","minAge":4},{"event":"napier-invents-logarithms","year":1614,"label":"Napier Invents Logarithms","emoji":"📉","link":"As science grew, calculations got longer. Napier's logarithms of 1614 turned multiplication into addition, which made the hand sums of astronomers much quicker.","kidsLink":"Later, Napier found a trick that turns hard multiplying into adding. It saved scientists lots of time.","minAge":4},{"event":"descartes-coordinate-geometry","year":1637,"label":"Descartes' Coordinate Geometry","emoji":"📊","link":"Descartes then joined two old branches of maths. In 1637 he described curves with equations, bringing algebra and geometry together, an idea Fermat reached independently.","kidsLink":"Then Descartes used numbers and equations to describe shapes. Today's grid graphs are named after him.","minAge":4},{"event":"leibniz-publishes-calculus","year":1684,"label":"Leibniz Publishes Calculus","emoji":"∫","link":"With curves now described by equations, mathematicians could study how they change. Leibniz published his calculus in 1684, independently of Newton, with notation still in use today.","kidsLink":"With shapes now written as equations, Leibniz published calculus. His symbols are still used today.","minAge":4},{"event":"babbage-analytical-engine-1837","year":1837,"label":"Babbage designs the Analytical Engine","emoji":"⚙️","link":"Calculation now moved from paper to machinery. Babbage designed a mechanical Analytical Engine with a memory and a processor, to be programmed with punched cards. It was never built in his lifetime.","kidsLink":"Then Babbage drew plans for a computer made of gears. It would use punched cards to do many jobs.","minAge":4},{"event":"lovelace-first-algorithm","year":1843,"label":"Lovelace Publishes an Early Computer Program","emoji":"💻","link":"Babbage's design needed instructions to be useful. Ada Lovelace saw that the machine could do more than sums and wrote an algorithm for it, which is why she is often called the first programmer.","kidsLink":"Ada Lovelace saw that Babbage's machine could do more than add. She wrote a program for it.","minAge":4},{"event":"boolean-algebra","year":1854,"label":"Boolean Algebra","emoji":"💡","link":"A different thread of maths was needed too. Boole turned logic into algebra of true and false, the foundation later used for the circuits inside digital computers.","kidsLink":"Then Boole turned logic into math with true and false. Computer circuits use his idea.","minAge":4},{"event":"turing-computable-numbers","year":1936,"label":"Turing Imagines the Computer","emoji":"🧠","link":"In 1936 Turing asked what it means to compute a number at all. His imaginary machine, following simple instructions, became the basic model of what a general-purpose computer can do.","kidsLink":"Turing then imagined a machine that follows any steps. This idea became a model for how computers work.","minAge":4},{"event":"eniac","year":1945,"label":"ENIAC: a room-sized electronic brain","emoji":"💡","link":"Theory became hardware. ENIAC used about 18,000 vacuum tubes to calculate about a thousand times faster than earlier machines, and six women were among its first programmers.","kidsLink":"Then came ENIAC, a room-sized computer with 18,000 glowing tubes. It was very fast for its time.","minAge":4},{"event":"four-colour-theorem","year":1976,"label":"The four-colour theorem, proved by computer","emoji":"🗺️","link":"Once computers could check cases faster than any person, they began to take part in mathematics itself. In 1976 the four-colour theorem became the first major theorem proved with a computer's help.","kidsLink":"At last, computers began to help with math itself. One checked a big proof about coloring maps.","minAge":4}]},{"id":"the-story-of-music","title":"The story of music","emoji":"🎵","blurb":"From flutes carved from bird bone and mammoth ivory more than 40,000 years ago to songs streamed online. Follow how people everywhere made music, learned to write it down and record it, and finally sent it around the world.","minAge":10,"kidsCut":true,"lens":"art","group":"people-and-ideas","beats":[{"event":"the-oldest-known-music-ice-age-bone-flutes","year":-40000,"label":"The oldest known music: ice-age bone flutes","emoji":"🎶","link":"The story starts with the oldest musical instruments we have found: flutes carved from bird bone and mammoth ivory in German caves, some of them 42,000 to 43,000 years old.","kidsLink":"Our story starts with the oldest instruments ever found. Ice Age people made flutes from bone.","minAge":4},{"event":"jiahu-bone-flutes","year":-7000,"label":"Jiahu's bone flutes — music you can still play","emoji":"🎶","link":"Tens of thousands of years after the cave flutes, villagers in China again drilled finger-holes into bird bones. Their flutes are among the oldest that can still be played, so bone flutes were made in more than one place.","kidsLink":"Many years later, villagers in China also made flutes from bird bones. People far apart made music the same way.","minAge":4},{"event":"lyres-of-ur","year":-2500,"label":"The golden Lyres of Ur","emoji":"🪕","link":"By 2500 BCE the Sumerian city of Ur had stringed instruments too. Its royal tombs held decorated lyres and harps, among the oldest stringed instruments ever found, which shows music had a place at royal burials.","kidsLink":"Later, in the city of Ur, people made fancy harps with strings. They were found in royal tombs.","minAge":7},{"event":"hurrian-hymn","year":-1400,"label":"The oldest near-complete song: the Hurrian Hymn","emoji":"🎼","link":"The lyre turns up again in Ugarit, where scribes wrote a hymn on clay with notes for a singer and a lyre. It is the oldest nearly complete written music, so music could now be kept on a tablet.","kidsLink":"Next, scribes wrote a song on a clay tablet with notes for a singer and a lyre. It is the oldest written song that is nearly whole.","minAge":4},{"event":"pythagoras-and-the-mathematics-of-harmony","year":-530,"label":"Pythagoras And The Mathematics Of Harmony","emoji":"📐","link":"Around 500 BCE Greek thinkers asked why some notes sound good together. Greek tradition says Pythagoras tied pleasing sounds to simple number ratios, though the tuning itself is far older, from Mesopotamia.","kidsLink":"Then thinkers asked why some notes sound good together. Legend says Pythagoras found that pleasing notes match simple number patterns.","minAge":4},{"event":"bells-of-marquis-yi-of-zeng","year":-433,"label":"The bronze bells of Marquis Yi of Zeng","emoji":"🔔","link":"About a century later in China, the ruler of Zeng was buried with a set of 65 bronze bells that can still play a full scale, each bell sounding two notes: proof of skilled metalwork and music theory far from Greece.","kidsLink":"Later, in China, a ruler was buried with 65 bronze bells. They can play a full scale, and each bell makes two notes.","minAge":7},{"event":"the-natya-shastra","year":-200,"label":"The Natya Shastra","emoji":"💃","link":"In India the Natya Shastra gathered rules for music, dance and drama into one written work. Like the Greek and Chinese examples, it shows people building a theory of music that went beyond making it.","kidsLink":"In India, a sage named Bharata is said to have written rules for music, dance and plays. It is another way people wrote down how music works.","minAge":4},{"event":"seikilos-epitaph-complete-song","year":100,"label":"The Seikilos epitaph, a song carved in stone","emoji":"🎼","link":"The Hurrian hymn survives nearly whole, but the Seikilos pillar carries a whole short Greek song with its tune written above the words. It is the oldest complete song that survives.","kidsLink":"Then someone carved a whole short song on a stone pillar, with its tune above the words. It is the oldest complete song we have.","minAge":4},{"event":"gamelan-borobudur","year":800,"label":"Gamelan carved in stone at Borobudur","emoji":"🎶","link":"Far from the Mediterranean, the Borobudur temple in Java was carved around 800 CE with drums, flutes and strings. The reliefs are early evidence of the gamelan, a different music tradition that still lives on.","kidsLink":"Far away in Java, a temple has carvings of drums, flutes and strings. They are early clues to gamelan music, which people still play.","minAge":4},{"event":"al-farabi-writes-the-great-book-of-music","year":930,"label":"Al-Farabi Writes The Great Book Of Music","emoji":"📖","link":"The philosopher Al-Farabi wrote the Great Book of Music, covering theory, instruments and how sound affects feelings. It has been called a work of utmost importance for the music of the Middle East.","kidsLink":"Then a thinker named Al-Farabi wrote a huge book about music and how it can change our feelings.","minAge":4},{"event":"guido-of-arezzo-invents-the-musical-staff","year":1025,"label":"Guido Of Arezzo Invents The Musical Staff","emoji":"🎶","link":"Singers in Europe still had to learn chants by ear. Guido of Arezzo added lines for pitch and names for notes, so a singer could learn a new chant by reading it.","kidsLink":"Singers still had to remember chants by heart. Guido, a monk, invented lines and note names so they could read music instead.","minAge":4},{"event":"perotin-notre-dame-polyphony","year":1198,"label":"Pérotin weaves music into many voices","emoji":"🎶","link":"Written music grew more ambitious. At Notre-Dame in Paris, Pérotin wrote three- and four-voice music, some of the earliest written for that many voices in the West.","kidsLink":"Later, in Paris, Pérotin wrote music for three and four voices singing together.","minAge":4},{"event":"griot-epic","year":1250,"label":"Griots keep history alive","emoji":"🎶","link":"Not all music relied on the page. In West Africa griots kept history alive by memory, singing the Epic of Sundiata with the kora, so written notation was only one of several ways music travelled through time.","minAge":10},{"event":"petrucci-prints-odhecaton","year":1501,"label":"Petrucci prints a book of polyphonic music","emoji":"🖨️","link":"Polyphony could now be written down, and in 1501 Petrucci printed a whole book of polyphonic songs with movable type, so music could be copied and shared far more easily.","kidsLink":"In 1501 Petrucci printed a book of songs, so music could be copied and shared more easily.","minAge":4},{"event":"zhu-zaiyu-equal-temperament","year":1584,"label":"Zhu Zaiyu describes equal temperament","emoji":"🧮","link":"While printers in Italy spread notated music, Zhu Zaiyu in China worked out equal temperament by careful calculation in 1584: a tuning that divides the octave into equal steps.","kidsLink":"Later, in China, Prince Zhu Zaiyu used maths to tune music in equal steps.","minAge":7},{"event":"peri-euridice-earliest-surviving-opera","year":1600,"label":"Peri's Euridice, the earliest surviving opera","emoji":"🎭","link":"By 1600 composers in Florence were setting a whole story to sung music. Peri's Euridice, retelling the Orpheus myth, is the earliest opera that survives, since his earlier Dafne is lost.","kidsLink":"In 1600, Peri in Florence put a whole story to singing. His opera Euridice is the oldest opera we still have.","minAge":4},{"event":"cristofori-invents-the-piano","year":1700,"label":"Cristofori invents the piano","emoji":"🎹","link":"Around 1700, at the Medici court in Florence, the city of Peri's Euridice, Cristofori built a keyboard with hammers so the player could play soft or loud: the first piano.","kidsLink":"Around 1700 in Italy, Cristofori built a keyboard with hammers. It could play soft or loud, and it was the first piano.","minAge":4},{"event":"beethoven-ninth-1824","year":1824,"label":"Beethoven's Ninth Symphony","emoji":"🎶","link":"More than a century after the first piano, Beethoven, by then almost completely deaf, premiered his Ninth Symphony, and its Ode to Joy became an anthem of human brotherhood.","kidsLink":"Then Beethoven wrote his Ninth Symphony, even though he could hardly hear by then. Its Ode to Joy became a famous song about people coming together.","minAge":4},{"event":"phonograph-1877","year":1877,"label":"Edison's phonograph","emoji":"🔊","link":"Before Edison's phonograph, no machine could record a performance and play it back. After 1877 the sound itself could be kept and heard again, so a performance could outlive the musicians.","kidsLink":"Before this, no one could record music and hear it again. Edison's phonograph could record real sound and play it back.","minAge":4},{"event":"handy-hears-the-blues","year":1903,"label":"W. C. Handy hears the blues","emoji":"🎵","link":"In 1903, waiting for a train in Mississippi, Handy heard a man play guitar with a knife as a slide. He became one of the first to publish songs in the blues form, carrying the Delta blues to a far wider audience.","kidsLink":"W. C. Handy heard a man play guitar with a knife in Mississippi. He became one of the first people to write down and publish the blues.","minAge":4},{"event":"first-jazz-recording","year":1917,"label":"First Jazz Recording","emoji":"🎷","link":"Handy had put the blues on paper, and in 1917 the Original Dixieland Jass Band put New Orleans jazz on a record. Records let the sound reach people who had never been to New Orleans.","kidsLink":"In 1917 a band made the first jazz record that was sold. People far from New Orleans could now hear jazz.","minAge":4},{"event":"first-radio-broadcast-1920","year":1920,"label":"Radio broadcasting begins","emoji":"📻","link":"Records carried music to people who bought them. In 1920 KDKA in Pittsburgh aired one of the first scheduled public broadcasts, helping launch the age of radio.","kidsLink":"Records took music to homes one at a time. Then radio stations like KDKA, in 1920, sent shows to many homes at once.","minAge":4},{"event":"electric-guitar-frying-pan","year":1932,"label":"The Frying Pan, an early electric guitar","emoji":"🎸","link":"Strings got an electric voice too. The Frying Pan guitar of around 1932 used a magnetic pickup to make string sounds louder, and electric guitars later powered jazz, blues and rock and roll.","kidsLink":"Next, a guitar called the Frying Pan used a magnet pickup to make its strings much louder.","minAge":4},{"event":"columbia-records-launches-the-long-playing-recor","year":1948,"label":"Columbia Records Launches The Long-Playing Record","emoji":"💿","link":"Records changed too. In 1948 Columbia's long-playing vinyl record packed over twenty minutes of music onto each side, far more than older shellac discs.","kidsLink":"Records changed too. A new kind of record could hold over twenty minutes of music on each side.","minAge":4},{"event":"rock-and-roll-1954","year":1954,"label":"Rock and roll arrives","emoji":"🎸","link":"A new sound arrived in 1954: Bill Haley's Rock Around the Clock and a young Elvis Presley's That's All Right. Rooted in African-American rhythm and blues, rock and roll grew within a few years into a youth culture heard around the world.","kidsLink":"Then came a new sound. In 1954 Bill Haley and Elvis Presley made rock and roll records, and soon young people everywhere loved it.","minAge":4},{"event":"moog-synthesizer","year":1964,"label":"The Moog synthesizer makes electronic sound","emoji":"🎹","link":"Electric guitars had amplified a string. In 1964 Robert Moog's synthesizer went further and made sound from circuits, with no string or pipe at all, which opened new sounds to pop and rock.","kidsLink":"Electric guitars made strings louder. Then Robert Moog made an instrument that makes sound from electric circuits instead.","minAge":4},{"event":"hip-hop-birth-bronx","year":1973,"label":"Hip-hop is born in the Bronx","emoji":"🎤","link":"Records themselves became the instrument in the Bronx in 1973. DJ Kool Herc used two turntables to stretch the danceable breaks of records, and that party is widely seen as the birth of hip-hop.","kidsLink":"In the Bronx, DJ Kool Herc used two record players to stretch out the best dancing parts of songs. This was the start of hip-hop.","minAge":4},{"event":"walkman-1979","year":1979,"label":"The Sony Walkman","emoji":"🎧","link":"Records were played at home, and radio played whatever the station chose. In 1979 Sony's Walkman let one person carry their own music anywhere, making listening personal and portable.","kidsLink":"Records stayed at home, and radio played what the station chose. Then the Walkman let people carry their own music anywhere.","minAge":4},{"event":"compact-disc-1982","year":1982,"label":"The CD stores music with light","emoji":"💿","link":"The Walkman made music portable, and the compact disc in 1982 changed how it was stored. Tiny pits read by a laser replaced the needle and gave clear digital sound.","kidsLink":"Then came the CD in 1982. A laser read tiny pits on it, and it gave clear sound.","minAge":4},{"event":"napster-launches","year":1999,"label":"Napster Changes Music Forever","emoji":"🎵","link":"Music had gone digital on CDs. In 1999 Napster let people swap music files free over the internet, and it showed music could travel instantly online.","kidsLink":"Music on CDs was digital. Then, in 1999, Napster let people swap music files over the internet.","minAge":4},{"event":"spotify-launches-and-streaming-reshapes-music","year":2008,"label":"Spotify Launches And Streaming Reshapes Music","emoji":"📱","link":"Napster had been shut down, but people still wanted music online. Spotify, conceived partly as a legal alternative to piracy, offered a huge catalogue for a subscription, and listening shifted from owning songs to streaming them.","kidsLink":"People still wanted music online. Spotify, started in 2008, let them stream huge amounts of music instead of owning songs.","minAge":4},{"event":"streaming-becomes-top-music-revenue-us","year":2015,"label":"Streaming becomes the top music revenue in the US","emoji":"🎧","link":"Streaming services grew quickly in the 2010s. In 2015 they overtook online music stores as the largest source of revenue for the US music industry, and since 2016 they have made up a majority of it.","kidsLink":"Streaming kept growing. In 2015 it became the biggest source of money for music in the United States.","minAge":4}]}]