252–66 Million Years Ago

Mesozoic Era

The Mesozoic Era, the 'Age of Reptiles,' lasted 186 million years and is defined by the dominance of dinosaurs. After the devastating Permian extinction, life recovered slowly during the Triassic, but by the Jurassic, dinosaurs had diversified into a spectacular array of forms — from the towering sauropods to the armored stegosaurs. Pterosaurs took to the skies, and marine reptiles like ichthyosaurs and plesiosaurs patrolled the oceans. The Cretaceous saw the rise of flowering plants, the evolution of modern bird lineages from theropod dinosaurs, and the emergence of small mammals that would inherit the Earth. The era ended abruptly when the Chicxulub asteroid impact triggered the K–Pg mass extinction 66 million years ago.