Scientists believe that the earth looked much different during the dinosaur's lifetime than it does today; at the advent of dinosaur life, all of the landmass on earth made up one single super continent known as Pangea. Dinosaurs likely did not live on every part of Pangea, instead concentrating in certain areas, including the land that is now known as Argentina, which is the home of the oldest known dinosaur fossil. Certain dinosaur species may have been localized to certain parts of the world, including the T.Rex, which has only been discovered in fossils found in North America.
Dinosaurs roamed the earth for about 165 million years, which was a time of great geographical upheaval on the planet. Pangea began to separate and spread apart, eventually creating the distinct landmasses that currently form the six major global land masses. Dinosaur skeletons have been found in various locations across the globe, including China, the United States and Great Britain. There are likely other areas of dinosaur fossils on the planet that are undiscovered; it tends to be easiest to find dinosaur fossils in desert locations that are dry and barren. Such areas, which usually have exposed rock that makes it easier to find fossil specimens, include deserts in the U.S. State of Nevada and the Gobi Desert in Asia.