Cave of the Crystals or Giant Crystal Cave is a cave connected to the Naica Mine 300 metres below the surface in Naica, Chihuahua, Mexico. The main chamber contains giant selenite crystals, some of the largest natural crystals ever found.
Gigantic crystals in Mexico's Cueva de los Cristales, or Cave of Crystals. In two brothers drilling for lead & silver in a remote part of northern Mexico discovered the underground crystal incubator. Photo by Carsten Peter