Cave of the Crystals
Hidden nearly 1,000 feet beneath the ground in Naica, Mexico, is an implausible scene, one that could serve as the natural world's testament to the adage that truth is stranger than fiction. Most of us have held crystals in our hands, but here in the subterranean "Sistine Chapel of crystals," the translucent selenite specimens measure up to 36 feet in length and weigh up to 55 tons, making them some of the largest crystals known to man. The magical Cave of the Crystals is about 30 feet wide and 90 feet long, with a floor tiled in perfectly faceted crystalline blocks from which the giant mineral beams emerge. Clearly, this is where they've been hiding all the unicorns.