For history & culture, La Brea Tar Pits & Museum is hit or miss.
A genuinely weird and wonderful thing — real, still-bubbling tar pits that trapped saber-tooth cats and mammoths, with an active dig and a fossil-rich museum. The grounds are free and fun, but the museum is small and a bit dated, so it's a big hit for kids and curious adults more than a half-day for everyone.