LaBrea tar pits
The LaBrea tar pits are located in Los Angeles, California, in Hancock Park (formerly known as Rancho LaBrea). This natural attraction features heavy, sticky tar which oozes out of the Earth and fills the pits (la brea is Spanish for "the tar"). The tar is actually the scum from underground petroleum reservoirs.
Throughout history, countless numbers of animals became trapped in the tar pits. In the absence of oxygen, the remains of those animals were perfectly preserved. Paleontologists (scientists who study prehistoric life) have excavated (uncovered) the fossilized bones and skulls of numerous prehistoric species, including the imperial mammoth, mastodon, sabre-toothed cat, and giant ground sloth.