Bluff Dweller's Cave

Bluff Dweller's Cave is a show cave located just south of Noel, Missouri that was discovered in 1925 and opened to the public in 1927. The cave was formed in the Pierson Limestone during the Paleozoic Era. The cave's passages total over 4,000 ft in length, with two entrances beneath a limestone outcropping of the bluff.

Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).