The Atacama Desert covers much of northern Chile and is widely considered the driest non-polar desert.
The Atacama occupies a long strip between the Pacific Ocean and the Andes, extending through northern Chile and into parts of southern Peru. Some weather stations in its core have recorded no measurable rain for years, while other areas receive only tiny amounts. Because definitions and measurement periods differ, descriptions often distinguish the desert's exceptionally dry core from its wider region.
Its aridity has several causes. The cold Humboldt Current limits evaporation and helps produce stable air, the subtropical high-pressure belt suppresses rainfall, and the Andes block moist air arriving from the east. The result is one of Earth's most extreme terrestrial environments.
Despite its dryness, the Atacama is not lifeless. Coastal fog called camanchaca can provide moisture, and unusual rainfall events can trigger spectacular blooms of desert flowers. The region also contains valuable deposits of copper, nitrates, and lithium.
The Atacama's clear, dry air makes it ideal for astronomy. Major observatories, including facilities operated by the European Southern Observatory, stand on its high plateaus. Mars researchers also use its soils and landscapes as analogues for planetary field studies.