Digging for the Museum of Natural History in the La Brea tarpits of Los Angeles, California, USA. The Rancho La Brea tarpits in the heart of L.A. yielded more than 3 million fossils, among them huge mammoths, sabertoothed cats and giant ground sloths. These Ice Age animals had been trapped and entombed in the asphalt seeping from the ground some 25 000 years ago. Rancho La Brea is one of the world's richest and most famous fossil sites. Since the fossils are not petrified, but very well preserved entire skeletons can be assembled from the finds.