The Duñas de Yeso are unique in Mexico and are often compared to the White Sands National Monument in New Mexico. The dunes were formed over thousands of years by sand grains moved by the wind from deposits left on the banks of the Laguna Churince. Water on the lake has disappeared in the past few years. Conservationists fear that this process has now been interrupted, with unpredictable consequences for the dunes and its unique ecology.