The focal point of this near-vertical photograph is White Sands National Monument located in the large Tularosa Valley of south-central New Mexico. This valley has a true desert climate because fewer than 10 inches (25 centimeters) of precipitation fall per year. The whitish area in the center of the photograph is the world’s largest gypsum dune field, covering nearly 300 square miles (800 square kilometers). At the southwest corner of the White Sands National Monument is Lake Lucero, a playa (dry lake), which is the lowest point in the Tularosa Valley. Following summer rains, Lake Lucero holds some water, but it is dry most of the year. Superimposed over some of the surface gypsum is a variety of desert vegetation that has become acclimated to this harsh environment. The San Andres Mountains and the Sacramento Mountains flank the basin west and east, respectively. The very dark area in the northeast corner is part of an ebony-colored lava flow called malpais. Intersecting airport runways and a fairly long, rock test sled track (parallel lines oriented north-south) are part of Holloman Air Force Base, which is located east of the White Sands area. The city of Alamogordo is approximately 15 miles (24 kilometers) east of the Holloman complex.