Karst is a topography formed from the dissolution of soluble carbonate rocks such as limestone and dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. There is some evidence that karst may occur in more weathering-resistant rocks such as quartzite given the right conditions.
Wookey Hole Caves are a series of limestone caverns, a show cave and tourist attraction in the village of Wookey Hole on the southern edge of the Mendip Hills near Wells in Somerset, England. The River Axe flows through the cave. It is a Site of Special Scientific Interest (SSSI) for both biological and geological reasons. Wookey Hole cave is a "solutional cave", one that is formed by a process of weathering in which the natural acid in groundwater dissolves the rocks. Some water originates as rain that flows into streams on impervious rocks on the plateau before sinking at the limestone boundary into cave systems such as Swildon's Hole, Eastwater Cavern and St Cuthbert's Swallet; the rest is rain that percolates directly through the limestone. The temperature in the caves is a constant 11 °C (52 °F).
A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are also known as shakeholes, and to openings where surface water enters into underground passages known as ponor, swallow hole or swallet. A cenote is a type of sinkhole that exposes groundwater underneath. Sink and stream sink are more general terms for sites that drain surface water, possibly by infiltration into sediment or crumbled rock.
The Natural Bridge Caverns are the largest commercial caverns in the US state of Texas. The name is derived from the 60-foot (18 m) 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.
Kartchner Caverns State Park is a state park of Arizona, United States, featuring a show cave with 2.4 miles (3.9 km) of passages. The park is located 9 miles (14 km) south of the town of Benson and west of the north-flowing San Pedro River. Long hidden from view, the caverns were discovered in 1974 by local cavers, assisted by state biologist Erick Campbell who helped in its preservation.
Luray Caverns, previously 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 adorned with speleothems such as columns, mud flows, stalactites, stalagmites, flowstone, and mirrored pools. The caverns host the Great Stalacpipe Organ, a lithophone made from solenoid-fired strikers that tap stalactites of varied sizes to produce tones similar to those of xylophones, tuning forks, or bells.
A cenote is a natural pit, or sinkhole, resulting when a collapse of limestone bedrock exposes groundwater. The term originated on the Yucatán Peninsula of Mexico, where the ancient Maya commonly used cenotes for water supplies, and occasionally for sacrificial offerings. The name derives from a word used by the lowland Yucatec Maya—tsʼonoʼot—to refer to any location with accessible groundwater.
Skyline Caverns is a series of geologic caves and a tourist attraction located in Warren County, Virginia, one mile (1.6 km) south of Front Royal. The caverns were discovered by Walter S. Amos, a retired geologist and mineralogist from Winchester, Virginia, on December 17, 1937. Skyline Caverns is open year-round, offering guided tours through the caverns.
Carboniferous Limestone is a collective term for the succession of limestones occurring widely throughout Great Britain and Ireland that were deposited during the Dinantian Epoch of the Carboniferous Period. These rocks formed between 363 and 325 million years ago. Within England and Wales, the entire limestone succession, which includes subordinate mudstones and some thin sandstones, is known as the Carboniferous Limestone Supergroup.
The Blauhöhle is the largest known cave system in the Swabian Alps in southern Germany. The Blauhöhle presumably originated in a time when the Danube still flowed through the Blau valley. Since the shifting of the Danube, several small rivers, the Schmiech, the Ach, and the Blau, have flowed through this valley. The cave system begins about 21 meters under water at the base of the Blautopf. It continues west and northwest, rising and falling several times until after a horizontal distance of about 1,200 metres (3,900 ft) it comes above the level of ground water and opens into the second big air-filled chamber. The maximum depth of the cave under water is 42 metres (138 ft).
Carlsbad Caverns National Park is a national park of the United States 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.
The Caves of Nerja are a series of caverns close to the town of Nerja in the Province of Málaga, Spain. Stretching for almost 5 kilometres (3.1 mi), the caverns are one of Spain's major tourist attractions. Concerts are regularly held in one of the chambers, which forms a natural amphitheatre.
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.
The Parque Nacional de las Cavernas del Río Camuy is a cave system in Puerto Rico. It is located between the municipalities of Camuy, Hatillo, and Lares in northwestern Puerto Rico, but the main entrance to the park is located in Quebrada, Camuy. The caverns are part of a large network of natural limestone caves and underground waterways carved out by the third-largest underground river in the world, the Río Camuy. The cave system was "discovered" in 1958 and was first documented in the 1973 book Discovery at the Río Camuy (ISBN 0-517-50594-0) by Russell and Jeanne Gurnee, but there is archaeological evidence that these caves were explored hundreds of years ago by the Taíno Indians, Puerto Rico's first inhabitants. Over 10 miles of caverns, 220 caves and 17 entrances to the Camuy cave system have been mapped so far. This, however, is only a fraction of the entire system which many experts believe still holds another 800 caves. Only a small part of the complex is open to the public. The 268-acre park built around the cave system features tours of some of the caves and sinkholes, and is one of the most popular natural attractions in Puerto Rico. After restorations necessitated by Hurricane Maria, a destructive storm that struck Puerto Rico in 2017, the park re-opened on March 24, 2021. It then closed again from September 2022 until February 2023 due to Hurricane Fiona.
The 2010 Guatemala City sinkhole was a disaster on 30 May 2010, in which an area approximately 20 m in diameter and 90 m deep collapsed in Guatemala City's Zona 2, swallowing a three-story factory. The sinkhole occurred because of a combination of reasons, including Tropical Storm Agatha, the Pacaya Volcano eruption, and leakage from sewer pipes. The sinkhole resulted in 1 death.
Little Blue Lake is a water-filled sinkhole (“cenote”) in the Australian state of South Australia located in the state's south-east in the locality of Mount Schank about 20 kilometres (12 mi) south of the municipal seat of Mount Gambier. It is notable locally as a swimming hole and nationally as a cave diving site. It is managed by the District Council of Grant and has been developed as a recreational and tourism venue.
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 1973 Mount Gambier cave diving accident was a scuba diving incident on 28 May 1973 at a flooded sinkhole known as "The Shaft" near Mount Gambier in South Australia. The incident claimed the lives of four recreational scuba divers: siblings Stephen and Christine M. Millott, Gordon G. Roberts, and John H. Bockerman. The four divers explored beyond their own planned limits, without the use of a guideline, and subsequently became lost, eventually exhausting their breathing air and drowning, with their bodies all recovered over the next year. To date, they are the only known fatalities at the site. Four other divers from the same group survived.
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.
