Organ Pipe Cactus National Monument

Organ Pipe Cactus National Monument is a U.S. national monument and UNESCO biosphere reserve located in southern Arizona that shares a border with the Mexican state of Sonora. The park is one of the few places in the United States where the senita and organ pipe cactus grow wild. Along with these species, many other types of cacti and other flora native to the Yuma Desert section of the Sonoran Desert region grow in the park. Organ Pipe Cactus National Monument is 517 sq mi (1,340 km2) in size. In 1976 the monument was declared a Biosphere Reserve by UNESCO, and in 1977 95% of the monument was declared a wilderness area.