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 16 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. Geology The cave consists of Chert (known as the Lost River Chert), which is overlaid by the Ste. Genevieve Limestone and St. Louis Limestone, both of which were laid down in the middle to late Mississippian Period. The river appears above ground in three short sections before flowing into the mouth of the cave. The most interesting section is the blue hole, which is the cause of the Lost River being listed by Ripley's Believe it or Not as the "Shortest, deepest river in the world." Plumb bobs indicated that the blue hole was 437 feet deep, while the river itself is only 400 feet long. The blue hole is though in fact linked to a further underground river. This caused plumb bobs to be swept underground, returning erroneous measurements. According to Malcolm Field and Guanguan Li: In 1847, Thomas Kite provided the following description of the river and cave in his journal: First inhabitants Archaeologists at Western Kentucky University have uncovered a significant history of human presence dating from the Paleo-Indians at the end of the last ice age 10,000 years ago. The location of the cave and the valley provided area inhabitants with shelter and with safe and plentiful sources of food and water. Ten thousand years ago, the Kentucky climate was cooler and wetter. The landscape supported evergreen forest. The Paleo-Indian Cultural Tradition, also known as "big game hunters", roamed the forests in search of food and shelter. These humans utilized Clovis spear points to bring down such animals as the giant ground sloth, the woolly mammoth, and the mastodon. The inhabitants were nomadic groups, moving between