During the last Ice Age, mammals seeking drinking water wandered into natural pools of asphalt, where they became trapped by the sticky tar and died. These asphalt pools, which continue to seep up from inside the earth, trapped and killed many large and small prehistoric animals and plants over centuries. Over three million fossils of these ancient, extinct flora and fauna are on display at the La Brea Tar Pits. The tar pits allow visitors a glimpse at what the Los Angeles basin was like 25,000 years ago, when mammoths, giant sloths, and saber-toothed cats roamed the area. Visitors can also watch fossil bones being cleaned. The Tar Pits, though fascinating, will not fill a whole day, so consider walking across the street to the LA County Museum of Art afterward. Also, LACMA sometimes holds free outdoor concerts in the summer, so check online for the schedule.
http://www.tarpits.org(approve sites)