In 1922 American paleontologist Roy Chapman Andrews led an archeological expedition into Mongolia's Gobi Desert and uncovered one of the richest dinosaur graveyards in the world. Political conflicts forced him to leave before he had even scratched the surface of the treasure below. In 1997, two paleontologists, Mike Novacek and Mark Norell, were allowed to return, retracing Chapman's steps and unearthing some groundbreaking finds of their own.