The Dunas de Yeso are an extraordinary landscape of white gypsum dunes rising from the desert floor south of Cuatrocienegas town. The gypsum — calcium sulphate — precipitates from the evaporating spring water of the valley and accumulates into dunes that can reach several metres in height, shifting slowly with the wind. The whiteness of the sand against the blue desert sky and the surrounding mountains is striking and, to eyes accustomed to tan or red desert landscapes, genuinely surprising.
The dunes are accessible by a rough dirt road from town and can be explored on foot. There are no facilities at the dune field, so bring water and start early to avoid the worst of the heat. The dunes are most photogenic in the early morning and late afternoon when the light is raking and the shadows are deep. The surrounding salt flats (salitral) extend beyond the dunes and add to the otherworldly quality of the landscape.