March 9, 2009
Cave of Crystals, Mexico
Photograph by Carsten Peter, Speleoresearch & Films
This Month in Photo of the Day: National Geographic Magazine Features
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.
See more photographs from the November 2008 feature story "Cavern of Crystal Giants."