Millions of years ago, dinosaurs lived all over the Earth. Some were as tall as a five-story building. Some were as small as a chicken. They ruled the planet for over 165 million years.
Then one day, about 66 million years ago, something terrible happened. A giant rock from outer space — called an asteroid — came flying toward Earth. It was about six miles wide. That is bigger than a whole mountain!
The asteroid slammed into what is now Mexico. The crash was more powerful than a billion bombs going off at once. It made a hole 93 miles wide.
no sunlight!The crash sent dust and ash high into the sky. So much dust filled the air that it blocked the sunlight. Without sunlight, plants could not grow. Without plants, plant-eating dinosaurs had nothing to eat. Without plant-eaters, meat-eating dinosaurs had nothing to eat either.
The world got very cold and very dark. Slowly, almost all the dinosaurs died.
But not everything disappeared! Small animals like birds, tiny mammals, turtles, and crocodiles survived. Scientists now know that birds are actually a type of dinosaur — so dinosaurs did not completely go away!