The first paleontological expedition to discover the famous dinosaur eggs was led by Roy Chapman Andrews in 1923. This expedition also led to the discovery of fossil forests in the region, as well as remains of mammals, including the skeleton of the hornless rhinoceros, which was the largest known mammal in the world, measuring 6 meters high and 9 meters long. Bayan Zag, meaning "rich Saxaul," is an ancient Neolithic settlement where large dinosaur skeletons on display at the Ulaanbaatar Natural History Museum were found. Of the seven major groups of dinosaurs listed, only one, the Stegosaurus, did not come from Mongolia. Bayan Zag is located in the Bulgan sum, 70 km from the tourist camp of Gurvan Saikhan, in a desert area dotted with saxaul bushes, as the name suggests. The region used to be covered in immense forests, but now only the saxaul, or zag, remains.