Deep Time
Journey Through Geologic Time
Earth's history spans 4.6 billion years. The fossil record opens a window into three great eras of complex life — each with its own cast of extraordinary organisms.
541–252 Million Years Ago
Paleozoic Era
The era of ancient life — from the Cambrian Explosion that birthed most animal phyla to the Great Dying that ended it. Trilobites, early fish, amphibians, and the first forests dominated this 289-million-year span.
252–66 Million Years Ago
Mesozoic Era
The Age of Reptiles. Dinosaurs ruled the land, pterosaurs commanded the skies, and marine reptiles patrolled the seas. Flowering plants emerged, and the era ended with the catastrophic asteroid impact.
66 Million Years Ago – Present
Cenozoic Era
The Age of Mammals. After the dinosaurs vanished, mammals diversified explosively. Grasslands spread, ice ages sculpted continents, and eventually a bipedal primate began to reshape the planet.