Cretaceous Period

Many of the most famous dinosaurs, such as Tyrannosaurus and Triceratops, first appeared in the Cretaceous (kruh-TAY-shus) Period, which lasted from 144 to 65 million years ago. During this last part of the Mesozoic Era, the first flowering plants evolved, along with bees, wasps, and other insects.

Image credits: main image, © AMNH/R.Barber; story, © AMNH.