Here are some fascinating facts about dinosaurs:

1. The word "dinosaur" means "terrible lizard" in Greek.

2. Dinosaurs ruled the Earth for over 150 million years, from the Triassic to the Cretaceous period.

3. There were over 1,800 known species of dinosaurs, ranging from small feathered creatures to giant long-necked sauropods.

4. The largest dinosaur, Argentinosaurus, weighed over 80 tons and reached lengths of over 100 feet.

5. The fastest dinosaur, Velociraptor, could run up to 40 miles per hour.

6. Some dinosaurs had feathers, and scientists believe that birds evolved directly from theropod dinosaurs.

7. Stegosaurus had a brain the size of a walnut, despite its body being over 30 feet long.