Dinosaur sites: Flaming Cliffs, Gobi Desert, Mongolia . (Mongolian name: Bayan Zag)In the 1920's the expedition of the American Museum of Natural History, led by Roy Chapman Andrews, discovered in these cliffs the first known dinosaur nests, as well as skeletons of Protoceratops and Oviraptor. The site was named 'Flaming Cliffs' because of the vibrant red color the cliffs take under the late afternoon sun..