The Naica Mine of the Mexican state of Chihuahua is a working mine that is best known for its extraordinary selenite crystals. Located in Naica in the municipality of Saucillo, the Naica Mine, alead, zinc and silver mine operated by Industrias Peñoles, is Mexico’s largest lead producer. Caverns discovered during mining operations contain crystals of selenite (gypsum) as large as 4 feet (1.2 m) in diameter and 50 feet (15 m) long.

It seems like a Hollywood movie set; perhaps a place for Superman to get a little alone time–but Mexico’s Cave of Crystals is no artificial wonder. Discovered in 2000 when silver miners broke through a wall in a mineshaft, the cave features crystals measuring 30 feet, the largest in the world. Only a handful of geologists have ever had the chance to visit this natural wonder, and it seems likely that few ever will; not only are the conditions inside the cave quite inhospitable, soon it will be filled with water. Recently a television crew had the chance to get into the Crystal Cave to show them the amazing formations attached to the mines of Naica in northern Mexico. The conditions in the cave, however, make extended exploration difficult. According to the television crew, the temperature reaches 50 degrees centigrade (122°F) with humidity at 100 percent.

Here’s the documentary which have been shown on Discovery HD (5 parts) :