Life After the Dinosaurs: The Beginning of the Reign of Mammals.

After the meteor wiped out the dinosaurs 66 million years ago, the planet wasn't left empty. The Cenozoic Era witnessed the rise of the most fascinating and lethal monsters ever to walk the Earth: three-meter-tall birds with beaks capable of crushing bones, colossal snakes that swallowed whole alligators, and predatory mammals that dominated hostile landscapes.