Cave of Crystals, Mexico
Photograph by Carsten Peter, Speleoresearch & Films

Massive beams of selenite dwarf human explorers in Mexico’s Cave of Crystals, deep below the Chihuahuan Desert. Formed over millennia, these crystals are among the largest yet discovered on Earth.

This Month in Photo of the Day: National Geographic Magazine Features:http://ngm.nationalgeographic.com/2008/11/crystal-giants/shea-text