"As part of one of the world’s 35 biodiversity hot spots, San Diego and its environs are home to more species than many regions of similar size. To learn more, head to the Natural History Museum’s permanent Coast to Cactus in Southern California exhibition, where you can immerse yourself in large, 3-D models of the area’s unique habitats, like mountain forests and coastal sage zones. You can even climb into a multimedia-equipped Airstream trailer that comes alive with the sounds of desert critters at night, or crawl through a mudflat to see the animals that call it home. While at the museum, be sure to also check out the Cerutti Mastodon exhibit, which tells the story of the paleontologists who, in the 1990s, excavated fossils from a site in San Diego that suggest humans were in North America 115,000 years earlier than previously imagined. The show includes evidence like a mastodon tusk and rocks that scientists believe were once used to break bones."