Atacama Desert

Parts of the Atacama Desert haven’t had measurable rainfall in recorded history. The Atacama Large Millimeter Array (ALMA) observatory on the Puna de Atacama plateau sits at 5,050 metres above sea level, above most of the atmosphere’s water vapour, making it one of the best astronomical observation sites on Earth. These two facts – the aridity and the altitude – produce a landscape unlike anywhere else: volcanic peaks, geothermal fields, salt plains, and a sky that at night shows the Milky Way as a dense structural band rather than a faint smear.

The Atacama covers approximately 105,000 square kilometres in northern Chile, with San Pedro de Atacama (2,410 metres elevation) as the main visitor hub. San Pedro is a village of about 5,000 people that has become one of South America’s most developed adventure tourism bases. Everything costs more here than elsewhere in Chile due to remoteness. The logistics are handled, the accommodation ranges from budget hostel to expensive eco-lodge, and the daily tours to the main sites are well-organised.

The Main Attractions

Valle de la Luna (Moon Valley), 12 kilometres west of San Pedro, has salt plains, wind-eroded clay formations, and amphitheatre bowls where mineral colours range from buff to deep purple. Tours run from late afternoon to catch sunset, when the formations turn orange and gold. Night visits are the other option: the sky conditions make the Atacama one of the best places in the world for naked-eye astronomy.

El Tatio geysers at 4,320 metres are the highest geothermal field in the world. Tours depart at 4am, the geysers are most active in the first two hours after dawn when cold air produces the greatest steam-to-temperature differential, and tours return mid-morning. The cold at dawn at that altitude is significant – bring considerably more layers than you think you need.

Salar de Atacama is the largest salt flat in Chile, covering 3,000 square kilometres. The far end of the flat has the Laguna Chaxa and Laguna de los Flamencos – high-altitude flamingo habitats supporting three of the world’s four South American flamingo species. The pink birds against white salt and blue sky produce the most distinctive photography of the Atacama.

Laguna Cejar is a high-concentration salt lake where the water density supports floating without effort. Day trips from San Pedro include floating time, which is disorienting in a good way.

The Night Sky

The ALMA radio observatory and several private astronomy tour operators use the Atacama sky specifically because of conditions: minimal light pollution, very low humidity, high altitude, and 330+ clear nights per year. Tour operators in San Pedro run nightly astronomy sessions for $20-35 per person, using serious telescopes and explaining what you’re looking at. The combination of good equipment and appropriate dark-sky viewing conditions produces a qualitatively different experience from casual naked-eye observation.

Practical Notes

Calama airport (CJC), 100 kilometres from San Pedro, receives flights from Santiago (2 hours). Shared transfers to San Pedro cost CLP 15,000-20,000 per person. All activity tours are bookable through San Pedro operators; the main sites are difficult or impossible to reach independently without a car.

Altitude acclimatisation matters: San Pedro itself is 2,410 metres and El Tatio is 4,320 metres. Spend the first day doing nothing strenuous. Drink water constantly. If the altitude affects you, altitude medication (ask your doctor before traveling) helps significantly.