Lost River Cave

Lost River Cave is a seven-mile cave system located in Bowling Green, Kentucky. The Lost River originates outside of the cave and flows into it. The cave contains one of the largest natural entrances in the Eastern U.S. Boat tours are available year-round, but closed for Thanksgiving Day, Christmas Eve, Christmas Day, and New Year's Day. The river was once listed by Ripley's Believe it or Not as the "Shortest, deepest river in the world" because the blue hole is over 437 feet deep, while the river itself is only 400 feet long. In fact, the blue hole is only 15 feet deep, but is linked to a further underground river. The 72-acre cave property is jointly owned by Western Kentucky University and the non-profit Friends of Lost River Cave.

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