Top 100 Big History

The origin of the universe, approximately 13.8 billion years ago

First generation stars ignite from hydrogen and helium clouds, ~200 million years after the Big Bang

Galaxies begin to coalesce from clouds of gas and early stars, ~1 billion years after Big Bang

Stars forge heavier elements from hydrogen and helium in their cores

Massive first-generation stars explode as supernovae, seeding the cosmos with heavy elements

Our Sun and planetary disk form from a collapsing molecular cloud, ~4.6 billion years ago

Earth accretes from the solar nebula around 4.5 billion years ago

A Mars-sized body collides with early Earth, ejecting debris that forms the Moon

Water delivered by comets and asteroids pools on Earth's cooling surface ~4 billion years ago

First self-replicating molecules emerge in Earth's oceans ~3.8–4 billion years ago

Simple single-celled organisms without nuclei appear ~3.5 billion years ago

Cyanobacteria begin producing oxygen via photosynthesis ~2.7 billion years ago

Oxygen floods Earth's atmosphere ~2.4 billion years ago, transforming all life

Complex cells with nuclei emerge ~2 billion years ago, possibly via endosymbiosis

First multicellular organisms appear ~1.2 billion years ago

Earth nearly entirely freezes over multiple times between 850–635 million years ago

Rapid diversification of complex animal life ~541 million years ago

First plants move onto land ~470 million years ago

Insects evolve on land ~400 million years ago, becoming the most diverse animal group

Fish evolve limbs and lungs, crawling onto land ~375 million years ago

The Great Dying kills ~96% of marine species ~252 million years ago

Dinosaurs emerge as dominant land vertebrates ~230 million years ago

Small, warm-blooded mammals evolve from synapsids ~225 million years ago

Flowering plants appear ~130 million years ago, revolutionising ecosystems

A massive asteroid strikes Earth ~66 million years ago, ending the dinosaurs

With dinosaurs gone, mammals diversify explosively into all niches

Primates emerge and diversify ~55 million years ago

Apes and Old World monkeys split ~25 million years ago

Human and chimpanzee lineages separate ~6–7 million years ago

Early hominins begin walking upright ~4 million years ago

Homo habilis appears ~2.8 million years ago with larger brains and stone tools

First stone tool technology ~2.6 million years ago — humanity's first technology

Glacial cycles intensify ~2.6 million years ago, shaping human evolution

Homo erectus evolves ~1.9 million years ago with larger brains and Acheulean tools

Early humans learn to control fire ~1 million years ago, transforming diet and society

Homo erectus spreads from Africa into Eurasia ~1.8 million years ago

Neanderthals emerge in Europe and western Asia ~400,000 years ago

Anatomically modern humans evolve in Africa ~300,000 years ago

Evidence of complex language, art, and symbolic thought emerges ~100,000–70,000 years ago

Modern humans migrate out of Africa ~70,000 years ago, colonising the world

Humans reach Australia ~65,000 years ago via island-hopping

Spectacular cave paintings at Lascaux, Chauvet, and Altamira ~40,000–17,000 years ago

Humans enter the Americas across Beringia ~16,000–13,000 years ago

Mass extinction of large mammals (mammoths, ground sloths) coincides with human arrival

Ice sheets retreat ~11,700 years ago, reshaping continents and climate

Humans begin farming wheat and barley in the Fertile Crescent ~10,000 BCE

Dogs, cattle, sheep, pigs and horses are domesticated ~10,000–5,000 BCE

Göbekli Tepe and Jericho show organised permanent settlements ~10,000 BCE

Ceramic pottery revolutionises food storage and trade ~9,000–7,000 BCE

Uruk and Eridu become the world's first cities ~4,000–3,500 BCE

Sumerians develop cuneiform script ~3,400 BCE — the birth of recorded history

Copper-tin alloy (bronze) transforms tools and warfare ~3,300 BCE

Wheeled vehicles appear in Mesopotamia ~3,500 BCE

Ancient Egyptians build the Great Pyramid ~2,560 BCE — engineering marvel of the ancient world

Sophisticated urban civilisation with sewage systems at Mohenjo-daro ~2,600 BCE

First major written legal code established ~1,754 BCE in Babylon

Iron smelting spreads across Eurasia ~1,200 BCE, superseding bronze

Phoenicians develop a consonant alphabet ~1,050 BCE that ancestors all modern alphabets

Major philosophical and religious traditions emerge simultaneously ~800–200 BCE

Cyrus the Great builds the first true multicultural empire ~550 BCE

Athens develops democracy, philosophy, and science ~500–323 BCE

Alexander spreads Greek culture from Egypt to India ~336–323 BCE

Rome expands to control the Mediterranean world ~509 BCE–476 CE

Lydia mints the first standardised coins ~600 BCE, enabling complex commerce

Trade routes connecting China to Rome and India open ~130 BCE

Christianity emerges in Roman Judea and spreads across the empire ~30–300 CE

Rome falls to Germanic tribes in 476 CE, beginning the European Middle Ages

Muhammad founds Islam ~610 CE; Islamic civilisation becomes a world power

China leads the world in science, trade, and culture ~618–1279 CE

Norse seafarers explore and settle from Greenland to North America ~793–1066 CE

Genghis Khan builds the largest contiguous land empire in history ~1206–1368 CE

Bubonic plague kills ~75 million people across Eurasia ~1347–1351 CE

Moveable type printing democratises knowledge ~1440 CE

European contact with the Americas in 1492 begins the Columbian Exchange

Global transfer of crops, animals, people, and diseases reshapes civilisations ~1492–1600

Copernicus, Galileo, and Newton transform humanity's understanding of the cosmos ~1543–1687

~12 million Africans forcibly transported to the Americas ~1500–1800

Steam power and mechanisation transform production and society in Britain ~1760–1840

Democratic ideals overthrow monarchies and reshape governance ~1776–1789

Slave trade abolished in Britain 1807; US emancipation 1865; global movement spreads

Pasteur and Koch prove microorganisms cause disease ~1860–1880

On the Origin of Species published 1859, unifying all of biology

Industrial-scale warfare kills ~20 million ~1914–1918, reshaping global order

Bolsheviks seize power in 1917, launching the Soviet experiment

Global conflict kills ~70–85 million, including systematic genocide of 6 million Jews ~1939–1945

First nuclear weapons detonated 1945 — humanity gains existential destructive power

Watson, Crick, Franklin and Wilkins reveal life's code in 1953

Dozens of nations win independence from European empires ~1945–1975

High-yield crops and fertilisers dramatically increase food production ~1960s–1980s

Humanity leaves Earth: Sputnik 1957, Moon landing 1969

ARPANET evolves into the global internet ~1969–1991, connecting all humanity

First complete map of the human genome published 2003

China's economic reforms from 1978 lift 800 million out of poverty and reshape geopolitics

Scientific consensus on human-caused global warming emerges ~1988–2000s

Tim Berners-Lee invents the Web in 1991; smartphones and social media transform society

Trade, migration, and cultural exchange reach unprecedented scale ~1990s–present

Neuroscience and AI combine to begin mapping the connectome — understanding consciousness

CRISPR-Cas9 enables precise gene editing ~2012, opening an era of biological redesign

Deep learning and large language models transform every field ~2012–present

Humanity becomes a geological force shaping Earth's climate, biosphere, and future