United States of America

Mammoth Cave National Park

about 1 hour away from by plane

Mammoth Cave National Park is a U.S. National Park in central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. The official name of the system is the Mammoth-Flint Ridge Cave System for the ridge under which the cave has formed. The park was established as a national park on July 1, 1941. It became a World Heritage Site on October 27, 1981, and an international Biosphere Reserve on September 26, 1990.

The park's 52,835 acres (21,382 ha) are located primarily in Edmonson County, Kentucky, with small areas extending eastward into Hart County and Barren County. It is centered around the Green River, with a tributary, the Nolin River, feeding into the Green just inside the park. With over 390 miles (630 km) of passageways it is by far the world's longest known cave system, being well over twice as long as the second longest cave system, which is South Dakota's Jewel Cave with just over 150 miles (240 km) of known passageways.

Mammoth Cave developed in thick Mississippian-aged limestone strata capped by a layer of sandstone, making the system remarkably stable. It is known to include more than 390 miles (630 km) of passageway; new discoveries and connections add several miles to this figure each year. Mammoth Cave National Park was established to preserve the cave system.

The upper sandstone member is known as the Big Clifty Sandstone: thin, sparse layers of limestone interspersed within the sandstones give rise to an epikarstic zone, in which tiny conduits (cave passages too small to enter) are dissolved by the natural acidity of groundwater. The epikarstic zone concentrates local flows of runoff into high-elevation springs which emerge at the edges of ridges. The resurgent water from these springs typically flows briefly on the surface before sinking underground again at elevation of the contact between the sandstone caprock and the underlying massive limestones. It is in these underlying massive limestone layers that t...

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