A descent through 4.6 billion years
Unseen Eons
Earth before anyone could take a picture of it. Giants known only from bones, continents that broke apart, and the other kinds of people who once walked here, reconstructed from fossils, rocks and ancient DNA.
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Seen from 1598; gone by about 1690 Dodo A flightless pigeon from Mauritius, last reliably seen alive in 1662 and gone before anyone could photograph it 
About 14 500 to 5 000 years ago Green Sahara The Sahara as a land of grass, lakes and fishers, which came to an end about 5 000 years ago 
Drowned between about 10 000 and 7 000 years ago Doggerland The lost land that joined Britain to Europe, home to hunters until the sea rose over it 
About 12 900 to 11 700 years ago Younger Dryas A sudden return to near-glacial cold in the north, just as the last Ice Age was ending 
About 20 000 to 14 000 years ago Missoula floods A glacial lake that kept bursting through its ice dam and emptying across Washington towards the Pacific 
About 780 000 years ago until 1627 Aurochs The wild ox behind every cow on Earth, last seen in a Polish forest in 1627 
Exposed about 35 700 to 11 000 years ago Beringia The vanished land between Asia and Alaska, where the first Americans waited out the Ice Age 
About 26 500 to 19 000 years ago Last Glacial Maximum The coldest stretch of the last Ice Age, when ice stood more than 3 km high over Canada and the sea lay about 120 to 130 m lower 
Gone about 600 years ago Haast's eagle The largest eagle that ever lived, a hunter of giant moa in New Zealand's South Island 
About 125 000 to 10 000 years ago Dire wolf The real Ice Age hunter behind the legend, and not quite a wolf at all 
From about 1.4 million years ago, when the Aepyornis lines split, to about 1 000 years ago Elephant bird Flightless giants of Madagascar, relatives of the kiwi, with eggs that could weigh about 10 kg 
About 400 000 to 4 000 years ago Woolly mammoth The Ice Age elephant known from frozen bodies and cave paintings, which outlived the pyramids' first builders on a remote island 
About 300 000 to 13 000 years ago Cave lion A separate species of lion that shrank through the last Ice Age and left its bones in other animals' dens 
About 400 000 to 12 000 years ago Macrauchenia A long-necked, three-toed South American mammal whose nostrils opened on top of its skull 
About 400 000 to 12 000 years ago Megatherium A ground sloth as heavy as an elephant that probably reared on its hind legs to strip the trees 
About 74 000 years ago Toba eruption The largest eruption of the past 2 million years, which left a caldera about 100 km long in northern Sumatra 
About 250 000 to 24 000 years ago Cave bear A bear as big as the largest alive today, with a domed head and teeth for grinding plants 
About 450 000 to 14 000 years ago Woolly rhinoceros A shaggy rhino with a metre-long horn that it may have used to sweep snow off the grass 
From at least 400 000 to perhaps 30 000 years ago Denisovans A lost kind of human known first from a finger bone's DNA, and in 2025 finally given a face 
About 2 million to 7 800 years ago, with the last dates disputed Doedicurus A domed relative of armadillos, up to 4 m long, that swung a solid bone club from the end of its tail 
About 400 000 to 40 000 years ago Neanderthals Our closest extinct relatives, whose DNA lives on in most people alive today 
Land on and off from about 2.4 million years ago; last drowned by about 7 000 years ago Sundaland The lowland, now under shallow seas, that joined Borneo, Java and Sumatra to mainland Asia through much of the Ice Age 
About 1.9 million to 11 500 years ago Giant beaver A rodent about 2 m long, with ridged front teeth up to 15 cm, that lived on water plants 
From up to 1.9 million until about 12 800 years ago Short-faced bear A bear with its shoulders at eye level, neither as short-faced nor as predatory as its reputation 
About 2.5 million to 10 000 years ago Smilodon A cat with 28 cm sabres and a jaw that opened far wider than a lion's 
About 700 000 to 50 000 years ago Homo floresiensis A human relative about a metre tall, who lived on an Indonesian island with dwarf relatives of elephants and Komodo dragons 
About 1.5 million to 40 000 years ago Megalania The largest land lizard known, a relative of the Komodo dragon whose size has been argued over since 1859 
About 1.77 million to 40 000 years ago Diprotodon The largest marsupial known, a plant-eater often compared to a rhinoceros, that walked on its wrists and heels across Ice Age Australia 
About 335 000 to 236 000 years ago Homo naledi A small-brained human relative known from a single deep cave, and the centre of an argument about burial 
About 2 million to 40 000 years ago Thylacoleo A predator descended from plant-eaters, with blade-like cheek teeth, a hooked thumb claw and a long tail to brace on 
About 700 000 to 200 000 years ago Homo heidelbergensis A tall, heavy-browed human relative named from a single jaw, under a name researchers still argue over 
About 2 million to 110 000 years ago Homo erectus The first human with a body much like ours, and perhaps the longest-lived human species of all 
Gone 295 000 to 215 000 years ago Gigantopithecus The largest ape that ever lived, known only from its teeth and four jaws 
About 43 million to 25 500 years ago Terror birds Flightless hunters with beaks like axes, top predators of South America for 40 million years 
About 2.9 to 1 million years ago Paranthropus A side branch of the human family with giant jaws, which walked the same lakeshores as early Homo 
About 7 to 1 million years ago Sivatherium A heavy, short-necked relative of the giraffe, with broad ossicones behind the head and a smaller pair above the eyes 
About 3.85 to 2.95 million years ago Australopithecus afarensis Lucy's species: small-brained, about a metre tall, and already walking on two legs 
About 13 to 1 million years ago Deinotherium A distant relative of elephants, up to 4 m at the shoulder, with tusks that curved down and back from its chin 
About 5.8 to 4.4 million years ago Ardipithecus A possible early human relative from Ethiopia, with a big toe that could grip branches and legs that could walk 
About 5.33 million years ago Zanclean flood The Atlantic breaking through at Gibraltar to refill a sea that had shrunk to lakes, perhaps within a few years 
About 5.97 to 5.33 million years ago Messinian salinity crisis The Mediterranean cut off from the ocean and left to evaporate, its level falling, in recent estimates, by anything from 600 m to over 2 km 
About 7.2 to 6.8 million years ago Sahelanthropus A 7-million-year-old skull from a lakeshore in Chad, from close to the time our line split from the chimpanzees' 
About 9 to 6 million years ago Argentavis A 70 kg relative of condors, too heavy to keep flapping, that rode the rising air over Miocene Argentina 
About 23 to 3.6 million years ago Megalodon The giant shark known from its teeth, and slimmer and stranger than the films suggest 
About 9.9 to 8.9 million years ago Livyatan A sperm whale with teeth over a third of a metre long, which hunted other whales 
About 10 million years ago, from dated finds of its best-known species Chalicotherium A hoofless relative of horses and rhinos that walked on its knuckles and hooked branches down with long, clawed arms 
About 17.3 to 10 million years ago Platybelodon A small relative of elephants whose flat lower tusks sliced grass held taut by a flexible trunk 
About 34 to 23 million years ago Paraceratherium A hornless rhinoceros relative that stood far taller than an elephant and browsed the tops of trees 
About 45 to 19 million years ago Entelodonts A family of long-legged, huge-headed omnivores, nicknamed hell pigs, that were probably closer to hippos than to pigs 
About 38 to 34 million years ago Basilosaurus An early whale up to 20 m long, with a stretched, slim body, a long toothed snout and hind legs too small to walk on 
Sank from about 85 to 25 million years ago Zealandia A continent of about five million square kilometres, almost all of it under the sea 
About 60 to 58 million years ago Titanoboa A boa about 13 m long, its body reaching a person's hips, from the oldest known rainforest of South America 
About 250 to 14 million years ago Tethys Ocean The tropical ocean that once split the continents, now folded into mountains from the Alps to the Himalaya 
About 66.3 to 65.6 million years ago Deccan Traps Lava that flooded western India as the age of dinosaurs ended, and an argument still running over how much it mattered 
66 million years ago Chicxulub crater The buried scar of the asteroid that ended the age of dinosaurs, 66 million years ago 
About 215 to 56 million years ago, as a continent of its own Laurasia The northern continent of North America, Europe and Asia, cut off from Gondwana and then broken in two by the Atlantic 
About 335 to 175 million years ago Pangaea Nearly all the land on Earth in one piece, surrounded by a single vast ocean for 160 million years 
About 252 million years ago The Great Dying The worst mass extinction in Earth's history, when volcanoes in Siberia nearly ended life on the planet 
About 304 to 299 million years ago Meganeura A predatory griffinfly about 70 cm across the wings, patrolling open air 300 million years ago 
About 344 to 292 million years ago Arthropleura The largest arthropod ever to walk on land, a millipede relative longer than a person 
358.86 to 298.9 million years ago Carboniferous period Sixty million years of equatorial coal swamps and southern ice sheets, when four-limbed animals began to breed away from water 
Formed about 600 million years ago, broke apart from 184 million Gondwana The great southern continent, where forests once grew close to the South Pole 
About 382 to 359 million years ago Dunkleosteus An armoured fish with blades for teeth, top predator of the Devonian seas 
About 750 to 190 million years ago Panthalassa One ocean over most of the planet, whose floor has vanished without trace except for scraps stuck onto the continents 
About 539 to 519 million years ago Cambrian explosion The burst, about 539 million years ago, when many of the main kinds of animals appear in the fossil record 
About 575 to 538.8 million years ago Ediacaran biota Fronds, ribbed ovals and tiny worms that covered the sea floor before the Cambrian animals arrived 
About 717 to 635 million years ago Snowball Earth The times, about 700 million years ago, when ice may have reached the equator and covered the whole planet 
Formed about 1.26 to 0.9 billion years ago, broke apart from about 750 million Rodinia A supercontinent of bare rock with North America at its heart, assembled about a billion years ago 
About 2.46 to 2.06 billion years ago Great Oxidation Event The slow, unsteady rise of oxygen in the air, released by microbes about 2.4 billion years ago 
About 4 567 to 4 031 million years ago Hadean eon Earth's first half-billion years, named after hell but probably already wet, under a Moon three times as wide 4.57 billion years ago
The bottom of time
Below this there are no rocks left to read. Climb back up through one of the three collections.