A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word cave can refer to smaller openings such as sea caves, rock shelters, and grottos, that extend a relatively short distance into the rock and they are called exogene caves. Caves which extend further underground than the opening is wide are called endogene caves.
Mammoth Cave National Park is a national park in south-central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. The park's 52,830 acres (21,380 ha) are located primarily in Edmonson County, with small areas extending eastward into Hart and Barren counties. The Green River runs through the park, with a tributary called the Nolin River feeding into the Green just inside the park.
Colossal Cave Adventure is a text-based adventure game, released in 1976 by developer Will Crowther for the PDP-10 mainframe computer. It was expanded upon in 1977 by Don Woods. In the game, the player explores a cave system rumored to be filled with treasure and gold. The game is composed of dozens of locations, and the player moves between these locations and interacts with objects in them by typing one- or two-word commands which are interpreted by the game's natural language input system. The program acts as a narrator, describing the player's location and the results of the player's attempted actions. It is the first well-known example of interactive fiction, as well as the first well-known adventure game, for which it was also the namesake.
Crystal Cavern(s), also known throughout the years as Alabama Caverns and McClu(n)ney Cave, is a small cavern containing crystal formations located in Clay, Alabama, USA.
William Crowther is an American computer programmer, caver, and rock climber. He is the co-creator of Colossal Cave Adventure from 1975 onward, a seminal computer game that influenced the first decade of video game design and inspired the text adventure game genre.
The Natural Bridge Caverns are the largest known commercial caverns in the U.S. state of Texas. The name is derived from the 60 ft natural limestone slab bridge that spans the amphitheater setting of the cavern's entrance. The span was left suspended when a sinkhole collapsed below it.
Russell Cave National Monument is a U.S. National Monument in northeastern Alabama, United States, close to the town of Bridgeport. The monument was established on May 11, 1961, when 310 acres (1.3 km2) of land were donated by the National Geographic Society to the American people. It is now administered and maintained by the National Park Service. The National Monument was listed on the National Register of Historic Places on October 15, 1966.
Luray Caverns, originally called Luray Cave, is a cave just west of Luray, Virginia, United States, which has drawn many visitors since its discovery in 1878. The cavern system is generously adorned with speleothems such as columns, mud flows, stalactites, stalagmites, flowstone, and mirrored pools. The caverns are perhaps best known for the Great Stalacpipe Organ, a lithophone made from solenoid-fired strikers that tap stalactites of various sizes to produce tones similar to those of xylophones, tuning forks, or bells.
Jewel Cave National Monument contains Jewel Cave, currently the fifth longest cave in the world, with 215.05 miles of mapped passageways. It is located approximately 13 miles (21 km) west of the town of Custer in Black Hills of South Dakota. It became a national monument in 1908.
At 150.4 miles (242.0 km), Lechuguilla Cave is the eighth-longest explored cave in the world and the second deepest in the continental United States. It is most famous for its unusual geology, rare formations, and pristine condition.
Bluespring Caverns is a cave system located in Lawrence County, Indiana, approximately 80 miles (128 km) south of Indianapolis. The cave system is a karst and river type cave formation and drains a 15 miles² (38.8 km²) sinkhole plain. The cave contains 21 miles (34 km) of surveyed passages and is most notable for having the longest known subterranean river in the United States with approximately 3 miles (4.8 km) of navigable river.
Dos Ojos is part of a flooded cave system located north of Tulum, on the Caribbean coast of the Yucatán Peninsula, in the state of Quintana Roo, Mexico. The exploration of Dos Ojos began in 1987 and still continues. The surveyed extent of the cave system is 82 kilometers (51 mi) and there are 28 known sinkhole entrances, which are locally called cenotes. In January 2018, a connection was found between Sistema Dos Ojos and Sistema Sac Actun. The smaller Dos Ojos became a part of Sac Actun, making the Sistema Sac Actun the longest known underwater cave system in the world.
Carlsbad Caverns National Park is an American national park in the Guadalupe Mountains of southeastern New Mexico. The primary attraction of the park is the show cave Carlsbad Cavern. Visitors to the cave can hike in on their own via the natural entrance or take an elevator from the visitor center.
Germany Valley is a scenic upland valley high in the Allegheny Mountains of eastern West Virginia originally settled by German farmers in the mid-18th century. It is today a part of the Spruce Knob–Seneca Rocks National Recreation Area of the Monongahela National Forest, although much ownership of the Valley remains in private hands.
Hellhole is a large and deep pit cave in Germany Valley of eastern West Virginia. It is the seventh longest cave in the United States and is home to almost half of the world's population of Virginia big-eared bats. At 737 feet (225 m), Hellhole is the deepest of several caves in the Valley.
The Grand Canyon Caverns, located just a few miles east of Peach Springs, Arizona, lie 210 feet (64 m) below ground level. They are among the largest dry caverns in the United States. Dry caverns comprise only 3% of caverns in the world. Because of the lack of water, stalagmites and stalactites are rare in the caverns.
In geography, an abîme is a vertical shaft in karst terrain that may be very deep and usually opens into a network of subterranean passages. The term is borrowed from French, where it means abyss or chasm.
Ash Hole Cavern is a limestone cave system in Brixham, Devon, England. There is evidence of human habitation since Neolithic times, and archaeological excavations have been conducted, with several artefacts found. It has been a scheduled monument since 1966.
The Fisher Ridge Cave System is a cave system located in Hart County, Kentucky, United States, near Mammoth Cave National Park. As of November 2019 it had been mapped to a length of 130.001 miles (209.216 km), making it the fifth-longest cave in the United States and the tenth-longest in the world.
