The White Sands National Monument is a U.S. National Monument located 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. The plant’s roots hold a pillar of sand in place, while the surrounding sands are shifted by wind erosion.