VALLE DE LA LUNA
Valle de la Luna: inside the Atacama's Valley of the Moon
How an ancient salt lake became a lunar landscape of dunes and pillars, why sunset is the moment to see it, and what to look for in the Cordillera de la Sal.
See Atacama tours on GetYourGuide ↗A seabed turned inside out
Valle de la Luna sits inside the Cordillera de la Sal, a range of hills about 13 km from San Pedro de Atacama built from an ancient salt lake bed. Millions of years of sediment — sandstone, clay, and thick layers of salt and gypsum — were folded and lifted skyward as the Andes rose, then carved by wind and rare flash floods into the ridges, dunes and hollows visitors walk through today. It's one of the clearest places on earth to watch tectonic uplift and erosion working on salt and clay rather than ordinary rock, which is exactly why the resulting shapes look like nowhere else nearby.
The Three Marys and the Great Dune
Two features anchor most visits: Las Tres Marías, a trio of wind-eroded salt-and-clay pillars said to resemble robed figures, and the Duna Mayor, a towering dune ridge that's often the vantage point for sunset. Between them run galleries of exposed salt crystal, dry lakebeds crusted white, and canyon walls striped in ochre and grey — a record of the different mineral layers laid down as the ancient lake dried out in stages over geological time. Walking between the two takes you through most of the valley's signature textures in a single loop, which is why guides usually route a visit around them.
Why the valley crackles
On quiet stretches near the salt formations, some visitors report a faint crackling or popping sound underfoot or in the surrounding rock. It's commonly attributed to salt crystals expanding and contracting as temperatures swing sharply between the heat of the day and the cold of the desert night, though the exact mechanism isn't something a casual visit can verify on the spot. Treat it as one of the valley's small, atmospheric details rather than a guaranteed show — some days it's noticeable, others it isn't, and no guide can promise which kind of visit you'll get.
The sunset ritual
Most tours time the valley for late afternoon, building toward sunset from a viewpoint over the dunes. As the light lowers, the salt-streaked rock shifts through gold, rust and violet in a way that's particular to the Cordillera de la Sal, since the mineral content in the rock reflects colour differently than plain desert stone does elsewhere. It's a shorter visit relative to a full-day excursion into the altiplano, which is exactly why Valle de la Luna pairs so naturally as a half-day add-on around the longer, higher-altitude trips that make up the rest of an Atacama itinerary.
A protected sanctuary
Valle de la Luna was declared a Santuario de la Naturaleza — a legally protected nature sanctuary — in 1982, which is why access runs through marked paths and viewpoints rather than free wandering across the dunes. The formations are soft and erode easily underfoot, so staying on the trail isn't just a rule for its own sake; it's what keeps the salt pillars and dune ridges intact for the next visitor rather than gradually worn away by foot traffic. Guides typically explain, on arrival, which stretches are open to walk and which are lookout-only, and it's worth actually listening rather than treating it as boilerplate.
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