The Day the Mesozoic Era Died

In the video they talked about how the Mesozoic Era came to an end, how they figured out how, and how life was post- asteroid. Geologists and paleontologists had spend years trying to figure out what the KT boundary was telling, and after looking at it all around the world, they came to the conclusion that an asteroid had hit the earth, that was the size of Mt. Everest. After the asteroid hit, the earth heated up and killed off all the dinosaurs and 60% of the plant life. Evidence of life below and above the KT boundary is extremely different, there hasn't been a dinosaur fossil found above the boundary anywhere in the earth. After the strike, life such as mammals and small reptiles that had big populations, somewhat survived. Then, the age of mammals began.