For anyone who's seen the original Richard Donner "Superman" movie, the cave might even conjure memories of the titular hero's Fortress of Solitude, with giant translucent crystals jutting out ...

The Cave of Crystals, also known as the Giant Crystal Cave, is a cave connected to the Naica Mine at a depth of 300 meters (980 ft) in Naica, Chihuahua, Mexico. It takes the form of a chamber ...