Caves harbor some of the most unique natural formations and animals in the world, and they might exist right beneath your feet without you ever knowing they’re there. Check out these fascinating facts about caves.

Long Time Coming

Caves take between 10,000 and 100,000 years to make. Water mixes with carbon dioxide to erode limestone rocks slowly to form underground caverns.

Up or Down?

Stalagmites grow up from the floor, while stalactites hang from the ceiling. Both formations need water to occur.

Animals Live There

Animals that spend their entire lives in caves are called troglobites. Blind salamanders and flatworms depend on caves for survival. Bats and raccoons are trogloxenes, or animals that live in caves part of the time.

That’s A Big Cave

The aptly named Mammoth Cave National Park in Kentucky has more than 400 miles of passages, making it one of the largest caves in the world.

Caves Underneath?

Visible sinkholes on top of the ground indicate cavern systems underneath.

Bad to the Bone

Big Cave at Carlsbad Caverns covers 14 acres underground as one of the largest single rooms in a cave. The deepest chamber in this system is more than 1,000 feet underground.

Music Lovers

Luray Caverns in Virginia features the world’s only Stalacpipe Organ that plays music. People play music with rubber-tipped mallets on stone formations to create the sounds.

The Cave State

Missouri, nicknamed the Cave State, has more than 6,000 caves. Up to 23 of them offer tours to the public, including Meramec Caverns, the largest cave in Missouri. Check out what it’s like to see thousands of bats flying out of a cave at once.