The La Brea Tar Pits are a group of tar pits in urban Los Angeles, around which Hancock Park was formed. The pits are one of the world's best and most important sources of Ice Age fossils.

Tar pits form when crude oil seeps to the surface through fissures in the Earth's crust, and when the light fraction of the oil evaporates it leaves behind the heavy tar or asphalt, in sticky pools. The La Brea tar pits have been seeping for tens of thousands of years, and has been traditionally used by local native Americans as glue and as waterproof caulking for baskets and canoes. But for the animals, these tar pits meant death. Over many centuries, hundreds of animals have fallen into the pits, become trapped and lost their lives, but the sticky gooey mass has preserved their bones. Many of these animals are now extinct, so the bones and fossils recovered from the La Brea tar pits are priceless today.

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