Lake Lucero is part of the White Sands National Monument but is located within the White Sands Missile Range. Lake Lucero is pretty cool because it's the source of the white sand (gypsum) that makes up the sand dunes in the national monument. There are lots of gypsum crystals on the ground that crystallize after being washed down from the nearby mountains. They have a trip every month into Lake Lucero (you can't get into the missile range at other times) that coincided with our trip. In White Sands National Monument, we hiked the Alkali Flat trail, which is quite a pleasant walk over the white sand dunes.