Free Admission Tuesday at Natural History Museum - see INFO below. The Natural History Museum of Los Angeles County is the largest natural and historical museum in the western United States. Its collections include nearly 35 million specimens and artifacts and cover 4.5 billion years of history. This large collection comprises not only of specimens for exhibition, but also vast research collections housed on and offsite.The museum is associated with two other museums in Greater Los Angeles: the Page Museum at the La Brea Tar Pits in Hancock Park and the William S. Hart Ranch and Museum in Newhall. The three museums work together to achieve their common mission: "to inspire wonder, discovery, and responsibility for our natural and cultural worlds." More Info below.