The Atacama Desert is considered one of the driest places on Earth. Covering an area of 181,300 square kilometers, the Atacama Desert is bordered on the east by the main Andes mountain range, and a secondary Andes mountain range known as Domeyko extends to the west.
It extends from several kilometers south of the Chile-Bolivia border at approximately 30° south latitude. It is made up of salt flats, sand and lava flows and is over 20 million years old. The driest portion of this region is located south of the Loa River and west of the Domeyko range, near San Pedro de Atacama and Toconao, towns located a short distance from the ALMA Observatory.
© ALMA (ESO/NAOJ/NRAO)