Crystal (Un)clear Path
Some of our planet’s most massive and difficult-to-reach caves are still in the process of having their secrets revealed. Take a look at a collection of the best photos of these extreme caves recently featured in National Geographic.
Here, 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.