White Sands National Monument (Images of America: New Mexico)

The world's largest gypsum dune field, the 275-square-mile dunes of White Sands National Monument are a geologic oddity more than 250 million years in the making. Located in Southern New Mexico, the popularity of the monument draws nearly half a million visitors each year to the National Park Service's southwestern region. The area is protected from encroachment by the boundaries of the US Army's White Sands Missile Range and houses no less than 144 species of birds, 20 unique mammals, and 371 types of insects. The gypsum's beauty has been captured by photographers and filmmakers for more than a century. Both Hollywood and scientists alike have sought after the monument's stunning otherworldly visuals to mimic other countries and worlds. The deserts of Qatar were recreated for Transformers (2007), and the monument has been identified as a potential analog site for Mars. The White Sands National Monument is a U.S. National Monument located about 25 km (16 mi) southwest of Alamogordo in western Otero County and northeastern Doña Ana County in the state of New Mexico, at an elevation of 4235 feet (1291 m). The area is in the mountain-ringed Tularosa Basin and comprises the southern part of a 710-km2 (275-mi2) field of white sand dunes composed of gypsum crystals. It is the largest gypsum dune field in the world.--Wikipedia