Where are the Andes?
About 199 million years ago, near the beginning of the Jurassic period, in the time of the dinosaurs, the supercontinent of Pangaea broke up and the pieces began to float away from each other. The Pacific Ocean tectonic plate began to squeeze under the South America plate, pushing up the Andes mountains that now run all along the west side of South America.
The Andes mountains are far older than the Alps, the Rockies, or the Himalayas. They're the oldest high mountains in the world, though they are newer than the Appalachian mountains or the Ural mountains.