A cave or cavern is a natural void under the Earth's surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance underground. Caves which extend further underground than the opening is wide are called endogene caves.
Mammoth Cave National Park is a national park of the United States in south-central Kentucky. It encompasses portions of Mammoth Cave, the longest known cave system 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.
The Door Peninsula is a peninsula in eastern Wisconsin, separating the southern part of the Green Bay from Lake Michigan. The peninsula includes northern Kewaunee County, northeastern Brown County, and the mainland portion of Door County. It is on the western side of the Niagara Escarpment. Well known for its cherry and apple orchards, the Door Peninsula is a popular tourism destination. With the 1881 completion of the Sturgeon Bay Ship Canal, the northern half of the peninsula became an island.
Wes Skiles Peacock Springs State Park is a 733-acre (297 ha) Florida State Park located on Peacock Springs Road, two miles (3 km) east of Luraville and on State Road 51, 16 miles (26 km) southwest of Live Oak, Florida. Activities include picnicking, swimming and diving, and wildlife viewing. Among the wildlife of the park are deer, bobcats, raccoon, squirrels, beaver and otters, as well as turkey, blue heron and barred owls. The park name commemorates the work of diver and explorer Wes Skiles. Prior to 2010 the park was known as Peacock Springs State Park. Amenities include a nature trail, six sinkholes, and Peacock and Bonnet Springs, with miles of underwater caves popular with cave divers. The two springs are tributaries of the Suwannee River. The park is open from 8:00 am till sundown year round.
The Leon Sinks Geological Area is located on the Woodville Karst Plain in southern and southwestern Leon County, Florida, United States. It is a mature karstic area on the Upper Floridan Aquifer. It is one of the most extensive underwater cave systems in the world and connects to Wakulla Springs.
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.
Buckner Cave is located in the karst topography of the Crawford Upland in Monroe County, Indiana, United States just outside Bloomington. The cave contains approximately 3 miles of known passage. It is managed by the Richard Blenz Nature Conservancy (RBNC) and resides in privately owned property. Over the years, the cave has been heavily vandalized with spray paint and trashed out from garbage including; food wrappers, broken bottles, empty beer cans, and spent calcium carbonate from carbide lamps. There is an ongoing effort to restore the cave to its natural state.
Marvel Cave is a privately owned cave located just west of Branson, Missouri, in Stone County. It is one of the main attractions of Silver Dollar City and is registered as a National Natural landmark.
Crystal Cave is a cave located in Wisconsin’s Pierce County, near the Town of Spring Valley on Highway 29. The cave was discovered in 1881 by local brothers George and William Vanasse. Crystal Cave is a multi-level solutional cave formed in dolomite bedrock in the Prairie du Chien Group. The dolomite was formed 485 million years ago during the Lower Ordovician Period when a warm shallow ocean covered much of Minnesota and Wisconsin. It is Wisconsin’s longest known cave.
The Sinks of Gandy — also called the Sinks of Gandy Creek, or simply "The Sinks" — are a modestly celebrated cave and underground stream at Osceola in eastern Randolph County, West Virginia, United States. The Sinks are on private property within the Monongahela National Forest.
Scott's Gulf is a canyon situated along the Caney Fork River in White County, Tennessee, in the southeastern United States. The canyon stretches for approximately 18 miles (29 km) as the Caney Fork drops from the top of the Cumberland Plateau down to the eastern Highland Rim. This remote section of the river is home to a wilderness area consisting of a largely undisturbed deciduous forest, numerous waterfalls, caves and other geological formations, and Class IV and Class V whitewater rapids.
Ledge View Nature Center is a 105-acre (0.42 km2) park and interpretive center. It is located two miles (3 km) south of Chilton, Wisconsin. The facility is part of the Calumet County Parks system operated by Calumet County.
Grassy Cove is an enclosed valley in Cumberland County, Tennessee, United States. The valley is notable for its karst formations, which have been designated a National Natural Landmark. Grassy Cove is also home to a small unincorporated community.
The Blue Hole of Santa Rosa, or simply the Blue Hole, is a circular, bell-shaped pool or small lake located along Route 66 east of Santa Rosa, New Mexico that is a tourist attraction and swimming venue, and one of the most popular dive destinations in the US for scuba diving and training. The Blue Hole is an artesian well and cenote that was once used as a fish hatchery.
Spider Cave, also known as Burnt Bluff Cave or 20DE3, is an archaeological site located on the Garden Peninsula near Fayette, Michigan. It was listed on the National Register of Historic Places in 1971.
Bar Pot is one of the entrances to the Gaping Gill cave system being located about 340 metres (370 yd) south of Gaping Gill Main Shaft, on Ingleborough in the Yorkshire Dales. It is a popular entrance into the system, being one of the easiest, driest, and having just two vertical pitches to contend with. It lies within the designated Ingleborough Site of Special Scientific Interest.
Warren's Cave is a dry karst cave in Alachua County, Florida. It is the longest dry cave in Florida, with more than 4 miles (6.4 km) of mapped passages. The cave is located on the margin of the Cody Scarp near the San Felasco Hammock Preserve State Park, northwest of the city of Gainesville. The property on which the entrance to Warren's Cave is located, the Warren Cave Nature Preserve, is owned by the National Speleological Society. Warren's cave was probably formed by a high water table when sea levels in the Quaternary Period were elevated close to 100 feet (30 m) above current sea level, corresponding to the Wicomico terrace.
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.
The geology of Wisconsin includes Precambrian crystalline basement rock over three billion years old. A widespread marine environment during the Paleozoic flooded the region, depositing sedimentary rocks which cover most of the center and south of the state.
Cave diving is underwater diving in water-filled caves. The equipment used varies depending on the circumstances, and ranges from breath hold to surface supplied, but almost all cave diving is done using scuba equipment, often in specialised configurations with redundancies such as sidemount or backmounted twinset. Recreational cave diving is generally considered to be a type of technical diving due to the lack of a free surface during large parts of the dive, and often involves planned decompression stops. A distinction is made by recreational diver training agencies between cave diving and cavern diving, where cavern diving is deemed to be diving in those parts of a cave where the exit to open water can be seen by natural light. An arbitrary distance limit to the open water surface may also be specified. Despite the risks, water-filled caves attract scuba divers, cavers, and speleologists due to their often unexplored nature, and present divers with a technical diving challenge.
