Travel guide to Llano Chajnantor in Chile

Llano Chajnantor is an arid high mountain plateau at an elevation of 5.042m (16,541ft) above sea level, located in El Loa Province, in the Antofagasta Region of Chile. It's one of the highest roads of the country.

Llano Chajnantor

Where is Llano Chajnantor?

Set high in the Atacama Desert in the Andes mountains, in the western side of the Puna de Atacama, the high mountain plateau is at the same latitude as deserts in southern Africa and central Australia. Located some 40 km east of the village of San Pedro de Atacama, it’s a truly unique and unusual place on a lunar landscape. Due to its otherworldly appearance, the area has been used as a location for filming Mars scenes. The zone has an exceptionally arid climate, inhospitable to humans. Atacama Desert is considered as one of the driest places on Earth.

Why is Llano Chajnantor famous for?

Tucked away in the northeastern part of the country, the arid high plateau is home to the Atacama Large Millimeter/submillimeter Array (ALMA), the biggest astronomical observatory on Earth. It’s an astronomical interferometer of radio telescopes. It’s the world's most powerful observatory for studying the universe at the long-wavelength millimeter and submillimeter range of light. The extremely dry conditions, where the air is too thin for humans to work without oxygen, is the ideal location for the array because it limits environmental and other factors that would interfere with the antenna’s operation if it were closer to sea level. The area almost every night is clear of clouds and free of light-distorting moisture.

Can you drive to Llano Chajnantor?

The private road to the plateau is totally unpaved. Starting at the paved Ruta 27, the road is 14.3 km (8.88 miles) long. Do not take this drive if you have respiratory problems or any type of heart condition as the altitude is sufficient to affect human function. Children under 16 years are not allowed to go up. Only ALMA certified vehicles and drivers with an ALMA “driver’s license” are allowed to drive.