In the park, there are ponds of bubbling black naturally-occurring asphalt. Methane fills the air. Sometimes you'll find asphalt randomly leaking out of the grassy ground. But here's why the tar pits are so awesome: They've been pulling the skeletons of Pleistocene animals out of the asphalt. Mastodons, saber-toothed cats, dire wolves, mammoths, ground sloths. You can see the skeletons in the museum. Did you know that lions and horses and camels used to live in the Americas? That the ancestors of sloths looked like ginormous mole-beavers? That dire wolves had penis bones? That mammoth tusks could be as thick as my thigh, or twice as long as I am tall? That the saber-toothed cat is not actually a member of the cat family? That their jaws could open as wide as 90 degrees?
In addition to visiting the tar pits, one of my goals for this trip was to visit the Museum of Jurassic Technology, but due to circumstances beyond my control I'm unable. I'm completely bummed. I found out about the museum by reading Mr. Wilson's Cabinet of Wonder by Lawrence Weschler, and I highly recommend it, especially if you enjoy having your mind blown.