The Mesozoic Era extinctions formed the world as we know it today. Read about what caused them and which animals survived.

About 66 million years ago, an asteroid slammed into the planet, wiping out all non-avian dinosaurs and about 70% of all marine species. But the crater it left behind in the Gulf of Mexico was a ...

Small fossils show mammals moved to the ground before the dinosaurs vanished. New plants changed habitats, giving better food ...