Coming out of the beautiful mountains of New Mexico you quickly descend and hit the desert floor which is one of the most “not” beautiful deserts I have seen. Rising out of the center is a frosted topping of white sand extending for miles. These are the white sands of New Mexico. Turning off the ugly road you enter a pristine and almost overly bright landscape. The sand consists of gypsum that is rarely found as sand. Normally, rain would dissolve the gypsum and carry it to the sea. The Tularosa Basin is enclosed, meaning that it has no outlet to the sea and that rain that dissolves gypsum from the surrounding San Andres and Sacramento Mountains is trapped within the basin. Thus water either sinks into the ground or forms shallow pools which subsequently dry out and leave gypsum in a crystalline form, called selenite, on the surface. Groundwater that does flow out of the Tularosa Basin flows south into the Hueco Basin. During the last ice age, a lake known as Lake Otero covered much of the basin. When it dried out, it left a large flat area of selenite crystals which is now the Alkali Flat. Another lake, Lake Lucero, at the southwest corner of the park, is a dry lake bed, at one of the lowest points of the basin, which occasionally fills with water. (some of this stolen from the web).