Description: The largest known cave system in the world, the Mammoth-Flint Ridge Cave System, as of 2022, has 426 miles of documented passages, and sits beneath the ground in Mammoth Cave National Park, established in 1941, and was listed as a UNESCO World Heritage Site in 1981, the only designation in the state of Kentucky. The park is also an International Biosphere Reserve, designated in 1990, and an International Dark Sky Park, designated in 2021. The Mammoth-Flint Ridge Cave System formed in Mississippian Limestone rock underneath a Big Clifty Sandstone cap, which has formed several stable arched passages of varying sizes from the intrusion of water into the rock layers, with the less porous sandstone cap preventing water intrusion at most locations, which have kept the caverns beneath intact and stable for eons. The water that passes through the cave system drains into the adjacent Green River, and has continuously eroded deeper into the rock along with the river. The cave is home to endemic species of organisms that have adapted to the dark conditions within the cave system. The cave system was known to indigenous people, whom mined gypsum from the walls of the caves and explored the caves, with human remains, signs of human activity, and artifacts from their presence in the cave. The cave became known to European settlers in the 1790s, and it started being mined by Valentine Simon for saltpeter to create gunpowder in 1798, with the mining activities intensifying around the time of the War of 1812, and becoming an industrial-scale operation under the ownership of Charles Wilkins and Hyman Gratz, whom used slave labor to exploit the cave’s resources. In 1838, with the decline in value of saltpeter, the cave was sold to Franklin Gorin, whom operated the cave as a tourist attraction, but was sold to Doctor John Croghan the following year. Under Gorin and Croghan, Black slaves served as tour guides for visitors, with Stephen Bishop being the most notable of these guides. Bishop made many maps of the caves during the 1840s and 1850s, and was the first known person to cross Bottomless Pit and discover the River Styx and Mammoth Dome on the other side. Croghan attempted to run a Tuberculosis Hospital within the cave in 1842-1843, believing the stable temperatures and air would assist patients, but this was short lived. In 1886, the Mammoth Cave Railroad was built between Park City and the historic Mammoth Cave Hotel, which operated until 1931. The caves were mapped more accurately by German visitor Max Kämper in 1908, whom mapped the surface topography and used instruments to document the cave, allowing for the opening of new entrances to the caverns from the surface and being the most accurate maps of the caves until the 1960s. Sadly, this was not appreciated by the Croghan family, whose historic cavern entrance was threatened in status by these maps, and Kämper returned to Germany, where he died as a soldier during World War I’s Battle of the Somme in 1916. Starting in the 1920s, the land around the caves was purchased by the private Mammoth Cave National Park Association, with the park being officially authorized in 1926. Between 1933 and 1942, the park’s landscape was reforested and infrastructure was constructed by the Civilian Conservation Corps (CCC), part of the New Deal. Between 1954 and 1972, the cave system was further explored, culminating in the connection between the longer Flint Ridge System and wider Mammoth Cave being found, making it the longest known cave system in the world. Today, the park sees about half a million visitors annually, and contains the majority of the Mammoth-Flint Ridge Cave system, with some portions of the system extending east of the park’s boundaries under privately-owned land.

Image by w_lemay – CC BY-SA 2.0 – Wikimedia

Description: The largest known cave system in the world, the Mammoth-Flint Ridge Cave System, as of 2022, has 426 miles of documented passages, and sits beneath the ground in Mammoth Cave National Park, established in 1941, and was listed as a UNESCO World Heritage Site in 1981, the only designation in the state of Kentucky. The park is also an International Biosphere Reserve, designated in 1990, and an International Dark Sky Park, designated in 2021. The Mammoth-Flint Ridge Cave System formed in Mississippian Limestone rock underneath a Big Clifty Sandstone cap, which has formed several stable arched passages of varying sizes from the intrusion of water into the rock layers, with the less porous sandstone cap preventing water intrusion at most locations, which have kept the caverns beneath intact and stable for eons. The water that passes through the cave system drains into the adjacent Green River, and has continuously eroded deeper into the rock along with the river. The cave is home to endemic species of organisms that have adapted to the dark conditions within the cave system. The cave system was known to indigenous people, whom mined gypsum from the walls of the caves and explored the caves, with human remains, signs of human activity, and artifacts from their presence in the cave. The cave became known to European settlers in the 1790s, and it started being mined by Valentine Simon for saltpeter to create gunpowder in 1798, with the mining activities intensifying around the time of the War of 1812, and becoming an industrial-scale operation under the ownership of Charles Wilkins and Hyman Gratz, whom used slave labor to exploit the cave’s resources. In 1838, with the decline in value of saltpeter, the cave was sold to Franklin Gorin, whom operated the cave as a tourist attraction, but was sold to Doctor John Croghan the following year. Under Gorin and Croghan, Black slaves served as tour guides for visitors, with Stephen Bishop being the most notable of these guides. Bishop made many maps of the caves during the 1840s and 1850s, and was the first known person to cross Bottomless Pit and discover the River Styx and Mammoth Dome on the other side. Croghan attempted to run a Tuberculosis Hospital within the cave in 1842-1843, believing the stable temperatures and air would assist patients, but this was short lived. In 1886, the Mammoth Cave Railroad was built between Park City and the historic Mammoth Cave Hotel, which operated until 1931. The caves were mapped more accurately by German visitor Max Kämper in 1908, whom mapped the surface topography and used instruments to document the cave, allowing for the opening of new entrances to the caverns from the surface and being the most accurate maps of the caves until the 1960s. Sadly, this was not appreciated by the Croghan family, whose historic cavern entrance was threatened in status by these maps, and Kämper returned to Germany, where he died as a soldier during World War I’s Battle of the Somme in 1916. Starting in the 1920s, the land around the caves was purchased by the private Mammoth Cave National Park Association, with the park being officially authorized in 1926. Between 1933 and 1942, the park’s landscape was reforested and infrastructure was constructed by the Civilian Conservation Corps (CCC), part of the New Deal. Between 1954 and 1972, the cave system was further explored, culminating in the connection between the longer Flint Ridge System and wider Mammoth Cave being found, making it the longest known cave system in the world. Today, the park sees about half a million visitors annually, and contains the majority of the Mammoth-Flint Ridge Cave system, with some portions of the system extending east of the park’s boundaries under privately-owned land.

Image by w_lemay – CC BY-SA 2.0 – Wikimedia

Description: Mammoth_Cave_National_Park (Kentucky)

Image by merfam – CC BY 2.0 – Wikimedia

Description: Mammoth Cave National Park, Kentucky

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Description: Mammoth_Cave_National_Park

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Description: Location Mammoth Cave National Park Description Mammoth Cave National Park preserves the cave system and a part of the Green River valley and hilly country of south central Kentucky. This is the world's longest cave system, with more than 365 miles explored.

Image by National Park Service Digital Image Archives – Public domain – Wikimedia

Description: Mammoth Cave Parkway

Image by LittleT889 – CC BY-SA 4.0 – Wikimedia

Description: Rotunda Room, Mammoth Cave — Mammoth Cave National Park; Kentucky.

Image by Willis Thomas Lee – Public domain – Wikimedia

Description: Tourists inside of Mammoth Cave National Park, Kentucky, US.

Image by Jud McCranie – CC BY-SA 4.0 – Wikimedia

Description: Mammoth Cave National Park

Image by John Manard – CC BY-SA 2.0 – Wikimedia