The Atacama, the driest desert that is not a pole

Only the polar deserts of Antarctica are drier than the Atacama. It stretches for about a thousand kilometres along the north of Chile, a band of rock, sand, gravel and salt between the Pacific Ocean and the Andes. In parts of it, weather stations have recorded almost no rain at all over many years.

The reasons lie in its position. The cold Humboldt Current, flowing north along the coast, cools the air above the sea and stops rain clouds forming. To the east, the Andes block the moist air coming from the Amazon. And the desert lies in a belt of high pressure that keeps the skies clear. The result is a landscape that scientists have used to test equipment for Mars.

San Pedro de Atacama

San Pedro de Atacama is an oasis town at about two thousand four hundred metres, on the eastern edge of the desert, beneath the volcanoes of the Andes. It is a small place of adobe houses, dusty streets and a whitewashed church with a roof of cactus wood, and it is the base for exploring the region. People have lived in the oases here for thousands of years, and the town's archaeological museum tells their story. Above the town, on a hill, are the ruins of Pukará de Quitor, a stone fortress of the twelfth century.

Just outside the town, the Valley of the Moon is a landscape of eroded ridges, salt-crusted rock and great sand dunes, carved by wind and the rare floods. At sunset, the colours change from ochre to red to violet across the valley, with the volcanoes catching the last light beyond.

Salt, flamingos and high lagoons

South of San Pedro, the Salar de Atacama is the largest salt flat in Chile, a vast white crust of salt and mud with shallow lagoons scattered across it. Three species of flamingo feed in the lagoons, especially at Laguna Chaxa, filtering tiny shrimp and algae from the water. The village of Toconao, on the edge of the salt flat, has a small church with a separate bell tower and orchards fed by a stream.

Higher up, beyond the village of Socaire, the road climbs into the altiplano, the high plateau of the Andes, at more than four thousand metres. Here the Miscanti and Miñiques lagoons are a deep, startling blue beneath the volcanoes, edged with white salt and yellow grass, and herds of vicuña, a wild relative of the llama, graze nearby.

Geysers and stars

The El Tatio geyser field lies in the Andes north of San Pedro, at more than four thousand two hundred metres, one of the highest geyser fields in the world. Visits start before dawn, because the geysers are at their most spectacular at sunrise, when the columns of steam rise into freezing air. It is bitterly cold at that hour, and warm clothes are essential. Villages such as Machuca, a tiny settlement of adobe houses with a little church on a hill, lie along the way.

The clear, dry air and the lack of light pollution give the Atacama some of the best night skies in the world, and several of the world's great observatories have been built in the region. In San Pedro, small local observatories offer evening stargazing with telescopes, under a sky thick with stars and the Milky Way.

Just You's Chile: the Atacama to Patagonia, fifteen nights for solo travellers, includes San Pedro de Atacama, Toconao, Socaire and Machuca, with Santiago, Puerto Varas, Puerto Montt, Peulla, Chiloé, Punta Arenas and Puerto Natales.

Explore Worldwide's Highlights of Chile: Atacama to Paine, twelve nights in January, March, October, November and December, includes San Pedro de Atacama and El Tatio, with Santiago, Valparaíso, Viña del Mar, Puerto Montt, Puerto Varas, Punta Arenas, Magdalena Island and Torres del Paine.

The Atacama can be visited all year, though it can snow on the high passes in winter, from about June to August. Spring and autumn bring warm days and cold nights. Take time to adjust to the altitude in San Pedro before going higher, drink plenty of water, and protect yourself from the strong sun.