The cave system has formally been known as the Mammoth–Flint Ridge Cave System since 1972, when a connection was discovered between Mammoth Cave and the even-longer system under Flint Ridge to the north. As of 2022, more than 426 miles passageways had been surveyed, over 1.5 times longer than second-longest cave system, Mexico's Sac Actun underwater cave.
One of my favorite childhood memories was taking a tour of Mammoth Cave and the guide stopping us in a part of the cave known as the Great Room and then extinguishing all our light sources. That was my first experience with total darkness, darkness so deep it makes you question any other reality, and the immense impact those moments can have on one's psyche.
The cave, as you can imagine, has also spawned many tales of the supernatural which even taken with a grain of salt, make for great campfire fodder.