Since 1893 the Arizona State Museum (ASM) has been collecting, reserving, researching and interpreting the cultures of the Greater Southwest, including Arizona and northern Mexico. It is the oldest anthropological museum in the region, and has been located at the University of Arizona since 1893, in its first home in Old Main. The Museum now occupies two buildings. The north building was constructed in 1925 as the Main Library. Upon completion of the new Main Library, the ASM expanded into this building in 1977. The Museum specializes in materials relating to the prehistoric Hohokam, Mogollon and Anasazi cultures, as well as the living American Indian cultures of the area. Admission is free. The ASM Library is located on the second floor of the north building and is open to the public on a non-circulating basis. Exhibit galleries in both the North and South buildings are open 7 days a week.