White Sands National Monument

Area: 230sq.mi/596sq.km

Established: 1933

The White Sands National Monument is half an hour's drive southwest of Alamogordo in the south of New Mexico. It lies in the Tularosa basin, a northern offshoot of the Chihuahua Desert surrounded by hills. Here gleaming white gypsum sand has built up into an extraordinary landscape of dunes up to 60ft/18m high which are constantly being displaced by the wind. Only highly adapted forms of life can stand up to the extreme conditions of this arid and constantly changing habitat. Some plants, for example, have developed roots over 30ft/10m long in order to gain a foothold in the traveling dunes. Origins

Some 250 million years ago this area was occupied by a shallow sea on the bottom of which gypsum was deposited. The present hills were created by the upthrusting and folding of marine sediments. A large section of the earth's crust fell in and the Tularosa basin was formed. In the hills round the basin the deposits of gypsum were dissolved by rain, and water with a high gypsum content gathered in the Tularosa basin, which had no outlet, and formed a lake, now known as Lake Lucero. The lake repeatedly dried out and the gypsum crystallized; and finally small grains of gypsum were blown by wind into the remarkable dunes we see today, which are now under protection as a National Monument.