The 4 U.S. Deserts (Chihuahuan, Sonoran, Mojave, and Great Basin). These springtime images are from three National Monument: 1. White Sands (1933) - located in NM, and situated in the Tularosa Basin (a "graben basin" - depressed block of land bordered by parallel faults, and also an "endorheic basin", no water flows out of it). The world's largest gypsum dunefield at 275 sq. mi. is located at this monument, which is part of the Chihuahuan Desert. 2. Chiricahua (1924) - located in southeastern AZ. Known as the "wonderland of rocks" and by the Chiricahua Apaches as the "land of standing-up rocks". It is also one of the "sky island" mountain ranges, and is part of the Chihuahuan Desert. 3. Organ Pipe Cactus (1937) in AZ - also a UNESCO Biosphere Reserve (1976), and is part of the Sonoran Desert. --- A National Recreation Area, Lake Meade - in NV, America's 1st National Recreation Area in 1947, part of the Mojave Desert. --- a State Park: Valley of Fire - in NV, the state's oldest 1935 and largest park, part of the Mojave Desert. --- and two U.S. Department of the Interior - Bureau of Land Management, Recreation Areas: 1. Imperial Dunes - in CA, the largest mass of sand dunes in the state, averaging 5 miles wide and 40 miles long in the state, also called Algodones Dunes "Cotton Dunes", part of the Sonoran Desert. 2. Aguirre Springs - in NM, the high wall and needle-like spires of the Organ Mountains, part of the Chihuahuan Desert.