terravelTerravel · Places · South America
Chile · South America
Atacama Desert
What is Atacama Desert, and where is it?
The Atacama Desert is a 1,600-kilometre strip of plateau along Chile's Pacific coast, stretching across 105,000 square kilometres between the Andes and the Chilean Coast Range. It ranks as Earth's driest non-polar desert, with some weather stations recording no measurable rainfall in recorded history.
Location and Geographic Boundaries
The Atacama Desert occupies northern Chile's Pacific coast, extending from near Arica in the north to near La Serena in the south. The desert forms a continuous strip roughly 1,600 kilometres long, wedged between the Andes mountains to the east and the Chilean Coast Range to the west. Peru borders the desert to the north, while the Chilean Matorral ecoregion marks its southern boundary. The less arid Central Andean dry puna lies to the east.
The terrain consists of a low-relief bench described as a giant uplifted terrace, with a coastal cliff forming the main topographical feature west of the Chilean Coast Range. South of latitude 19°30'S, the intermediate depression creates a series of endorheic basins—closed drainage systems with no outlet to the sea. North of this latitude, the depression drains toward the Pacific Ocean.
The Two-Sided Rain Shadow
The Atacama's extreme aridity stems from its position between two mountain chains tall enough to block moisture from both oceans. The Andes to the east prevent Atlantic moisture from reaching the region, while the Chilean Coast Range to the west blocks Pacific moisture. The cool, north-flowing Humboldt Current and the South Pacific anticyclone reinforce this drying effect. Average annual rainfall measures around 15 millimetres, though some locations receive only 1 to 3 millimetres yearly.
Evidence suggests the desert may have received no significant rainfall from 1570 to 1971—a span of over 400 years. Some weather stations have never recorded measurable rain. Hyper-arid conditions date back at least to the Miocene epoch, roughly 33 million years ago, when the opening of the Tasmania-Antarctic passage allowed cold currents to flow along South America's west coast, cutting off warm humid air from the Amazon Basin. The desert may be the oldest on Earth, with arid conditions possibly persisting for the last 200 million years.
Astronomical Research and Mars Analogue
The Atacama's high altitude, dry air, and near-total absence of light pollution make it one of Earth's premier sites for astronomical observation. Major observatories operate here, including the Atacama Large Millimeter Array (ALMA) and the Very Large Telescope. The region's extreme conditions and clear skies attract researchers studying the cosmos from some of the world's most advanced facilities.
The desert's soil composition and near-total absence of microbial life have made it a testing ground for Mars mission instruments. In 2003, researchers duplicated tests used by Viking 1 and Viking 2 Mars landers to detect life and found no signs in Atacama soil near Yungay. NASA uses the region to test instruments for future Mars missions. In 2014, a hyperarid site called María Elena South was identified as an even better Mars-like environment. Scientists have also reported a 'dark microbiome' of unfamiliar microorganisms in the desert, expanding understanding of life's limits on Earth.
Flora Adapted to Extreme Conditions
Over 500 plant species inhabit the Atacama despite its harsh environment. The llareta, one of the highest-growing wood species in the world, grows at altitudes between 3,000 and 5,000 metres. Its dense, pillow-like form measures 3 to 4 metres thick and concentrates heat from the day to survive cold nights. Growth rates of approximately 1.5 centimetres per year mean many llaretas exceed 3,000 years old. The plant produces a prized resin once harvested indiscriminately for fuel, making it endangered.
Common species include herbs and flowers such as thyme, llareta, and saltgrass. Where humidity permits, trees like the tamarugo (endemic to the Atacama), chañar, pimiento, and algarrobo grow. Cacti and succulents thrive in the dry climate, including the candelabro and cardon, which reach heights of 7 metres and diameters of 70 centimetres. In years with sufficient precipitation, the Atacama Desert flowering occurs from September to November, transforming parts of the landscape with seasonal blooms.
Human Settlement from Chinchorro to Mining Era
The Atacama has been inhabited since at least 7000 BCE, when the Chinchorro culture settled along its coast as sedentary fishermen. Their presence extended from Ilo in southern Peru to Antofagasta in northern Chile, concentrated in areas with fresh water. The Chinchorro became renowned for detailed mummification and funerary practices. Later, the Atacameño tribe inhabited the interior, building fortified towns called pucarás. During the Inca Empire, Aymara communities settled in the region as part of population transfer schemes.
Spanish colonial rule brought coastal towns that developed as ports for silver exports from Potosí and other mining centers during the 16th, 17th, and 18th centuries. In the 19th century, discovery of sodium nitrate deposits transformed the region into a zone of conflict between Chile, Bolivia, and Peru, culminating in the War of the Pacific. Chile annexed most of the desert, and the population grew through migration from central Chile. The nitrate industry declined in the 20th century following the invention of synthetic nitrate in Germany. About 170 abandoned nitrate mining towns now litter the desert, including Humberstone, Chacabuco, and Santa Laura.
Atacama Desert at a glance
Questions about Atacama Desert
Why is the Atacama Desert so dry?
The Atacama lies between two mountain chains—the Andes and the Chilean Coast Range—tall enough to block moisture from both the Pacific and Atlantic oceans. This two-sided rain shadow effect is reinforced by the cool Humboldt Current and the South Pacific anticyclone, creating conditions so arid that some areas have never recorded measurable rainfall.
What animals live in the Atacama Desert?
Despite extreme aridity, the desert supports adapted species including Humboldt penguins along the coast, Andean and Chilean flamingos on salt flats, and Darwin's leaf-eared mice. Iguanas, lava lizards, and salt flat lizards inhabit various zones. Larger mammals like guanacos, vicuñas, and South American gray foxes graze in areas with seasonal grass growth.
How old is the Atacama Desert?
The Atacama may be Earth's oldest desert. Hyper-arid conditions date back at least to the Miocene epoch, approximately 33 million years ago. Evidence suggests arid conditions may have persisted for the last 200 million years, since the Triassic period, making it geologically ancient and continuously dry.
What happened to the nitrate mining towns?
About 170 nitrate mining towns flourished during the 19th and early 20th centuries but were abandoned following the invention of synthetic nitrate in Germany in the first decade of the 1900s. Towns like Humberstone, Chacabuco, and Santa Laura now stand abandoned throughout the desert.
Why do scientists use the Atacama to test Mars instruments?
The Atacama's soil composition, near-total absence of microbial life, and otherworldly appearance closely resemble Martian conditions. NASA uses the region, particularly hyperarid sites like María Elena South, to test instruments for future Mars missions and study the limits of life on Earth.
Sources and further reading
This article was written from the reference material below, retrieved and reviewed for source alignment on September 13, 2026. Use official local sources for changing access or travel information.
About this page. Terravel combines its curated place catalog with credited photography and geographic reference data. Practical travel details can change; use the linked destination guide and official local sources when planning a trip. Send a correction.
Test yourself
Which South American place has never recorded measurable rainfall in some areas throughout recorded history?
The Atacama Desert in Chile is one of Earth's driest regions, with parts that have never received measurable rainfall in recorded history—a distinction that does not apply to the Paraná River (a major waterway), Colca Canyon (which receives seasonal precipitation), or Rocas Atoll (surrounded by ocean).
Can you place today's?
Atacama Desert is one of 266 places in Terravel. A new one every morning.
Go beyond the familiar in South America
Start with a place you know, then follow the map toward somewhere less expected.
