T-Rex lived in Western North America 68 to 65 million years ago, at the end of the Late Cretaceous Period.

Probably the most famous dinosaur of them all T Rex was one of the largest terrestrial carnivores of all time. It stood approximately 15 feet high and was about 40 feet in length, roughly six tons in weight. In its large mouth were six-inch long, sharp, serrated teeth.

The debate goes on as to whether it was a hunter or a scavenger, but it seems most likely it was both.
Though opinions vary it is thought it was well capable of running at 25mph.