At 150.4 miles (242.0 km), Lechuguilla Cave is the eighth-longest explored cave in the world and the second deepest in the continental United States. It is most famous for its unusual geology, rare formations, and pristine condition.
Largest known gypsum stalactites, Chandelier Ballroom (human at bottom gives scale)
Stalagmites, stalactites, and draperies by a pool
A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word cave can refer to smaller openings such as sea caves, rock shelters, and grottos, that extend a relatively short distance into the rock and they are called exogene caves. Caves which extend further underground than the opening is wide are called endogene caves.
Lechuguilla Cave, New Mexico, United States
Speleothems in Hall of the Mountain King of Ogof Craig a Ffynnon, a solutional cave in South Wales.
Exploring a lava tube in Hawaii.
Painted Cave, a large sea cave, Santa Cruz Island, California