Invited by the Mongolian Academy of Sciences to join them, a team of paleontologists from the American Museum of Natural History travelled in 1992 into the Gobi Desert of Mongolia. They followed in the tracks of the same museum's expedition of the 1920's. That earlier exploration, led by Roy Chapman Andrews, was organised to seek the origins of human beings in Central Asia. Instead, a treasure trove of remains was found from the final reign of the dinosaurs, including their eggs. Then and now, the scorching desert sands yield fossils that help piece together the history of life on Earth. The scientist seek answers to evolution's greatest riddles, such as the rise of the mammals with the demise of the dinosaurs, or how small carnivorous dinosaurs are closely related to birds.