[2] First surveyed in the 1960s,[3] it is one of the longest in the United States and the world.

[7][10][4] The cave formed in the Mississippian Greenbrier Group.

The oldest passage of the cave is said to be 4.1 million years old.

[11] The cave was formed by streams sinking down into the ground.

[12] The minor structures in the cave were influenced by thrust faults.