Cueva de los cristales

Cueva de los cristales (Cave of the Crystals) is a cave connected to the Naica Mine 300 meters below the surface in Naica, Chihuahua, Mexico. The main chamber contains giant selenite crystals, some of the largest natural crystals ever found.
The largest crystal found in the cave to date is 12 m long and 4 m in diameter and 55 tons in weight.