Valle de la Luna earns its name honestly. Wind and water have carved the terrain into sharp ridges, deep canyons, and salt-crusted formations that glow amber and crimson at sunset. You can bike there from town -- it is only a few kilometers to the entrance -- but the road is steep and sinuous, and afternoon temperatures can be suffocating year-round. Those who arrive by bicycle in the early morning have the valley nearly to themselves before the tour vans appear. A cave along the route is pitch black inside, worth exploring with a headlamp. Near the entrance lies Valle de Marte, where sandboarding down the dunes is permitted, though doing so in Valle de la Luna itself will earn you a fine. The sunset from the high viewpoints is the main event, and travelers have been known to barter for used entrance tickets from cyclists returning in the afternoon.

The drive to Geysers del Tatio begins at five in the morning, climbing through darkness to 4,100 meters where steam columns blast from the ground into air that can reach minus fifteen degrees Celsius in winter. The geysers are most dramatic at dawn, when the low sun catches the steam against a still-dark sky. Afterward, most tours stop at a thermal pool with views of the surrounding volcanoes -- not particularly warm, but the setting compensates. On the descent, wild vicunas graze near the road, tolerant of tourists who keep their distance but ready to bolt at a step too close. The fording of the Putana River is a spectacle that some visitors rate above the geysers themselves, with giant coots, flamingos in summer, and the occasional shy vizcacha. Altitude sickness is a genuine concern at nearly 4,500 meters on the road up, and the oxygen canisters that agencies claim to carry are usually just compressed air at one atmosphere.

Laguna Cejar floats you like the Dead Sea. The water is so saturated with salt that swimming face-down is dangerous -- the buoyancy can flip an unsuspecting swimmer, and people have drowned after panicking. Tour groups finish with pisco sours on the shore, which at 35 to 40 proof are more potent than their sweet-sour taste suggests. The surrounding salt flats reflect sunlight with the intensity of snow; sunglasses and long sleeves are essential unless you welcome blindness and burns. Farther afield, the Lagunas Altiplanicas -- Miscanti and Miniques -- sit above 4,200 meters, their turquoise waters ringed by volcanic peaks and whipped by winds that can bring the perceived temperature to freezing. The road crosses the Tropic of Capricorn, marked by a strange white cross that also indicates the old Inca road traversing the region, a detail most guides overlook.

San Pedro's archaeological heritage matches its natural spectacle. Aldea de Tulor, roughly 3,000 years old, is the oldest known settlement in the Atacama basin, its circular adobe structures preserved in remarkably intact condition. Four kilometers from town, the Pukara de Quitor is a 10th-century fortress whose summit offers sweeping views of the valley and the surrounding volcanoes. The Gustavo Le Paige Archaeological Museum on the Plaza de Armas holds a collection of Atacameno artifacts and objects acquired through ancient trade routes -- though the mummies that once drew visitors were removed years ago at the request of the indigenous community. The Hierba Buenas petroglyphs, along the road to Valle del Arcoiris, display over a thousand stone carvings spanning every period from the first caravaneers to the Inca occupation.

At 2,400 meters in the driest desert on Earth, San Pedro offers some of the clearest night skies accessible to ordinary travelers. Astronomical tour operators set up telescopes on the outskirts of town, where the absence of light pollution and atmospheric moisture reveals the Milky Way with a clarity that feels hallucinatory. The same atmospheric conditions that make the Atacama miserable for agriculture make it paradise for astronomy. ALMA, the world's most powerful radio telescope array, operates on the Chajnantor plateau an hour's drive to the south. Several other major observatories dot the surrounding desert. Most visitors who come for the geology and the geysers find that it is the sky, in the end, that they remember longest. San Pedro is reached by bus from Calama, ninety minutes away, where the nearest commercial airport connects to Santiago. There is no direct air service; the town's isolation is part of its identity.