Organ Pipe Cactus National Monument
Established in 1937, the Monument encompasses over 330,000 acres of lush Sonoran Desert, including 95% Wilderness. Its biological diversity led to a UNESCO World Biosphere Reserve designation in 1976. The human history is equally as diverse, dating back to the 1450s. With the adjacent lands of Cabeza Prieta National Wildlife Refuge, the BMG Military Range, Tohono O'dham Nation, and the Pinacate y Gran Desierto Biosphere Reserve, the Greater Organ Pipe Ecosystem protects over 4 million acres.