The Greenbrier River is a tributary of the New River, 162 miles (261 km) long, in southeastern West Virginia, in the United States. Via the New, Kanawha and Ohio rivers, it is part of the watershed of the Mississippi River, draining an area of 1,656 square miles (4,290 km2). It is one of the longest rivers in West Virginia.
Optymistychna is a gypsum cave located near the Ukrainian village of Korolivka, Chortkiv Raion, Ternopil Oblast. Approximately 264 km (164 mi) of passageways have been mapped within. As a result, it is the longest cave in Eurasia and the sixth-longest cave in the world, after Mammoth Cave, Sistema Sac Actun, Jewel Cave, Shuanghedong and Sistema Ox Bel Ha. It is also the longest gypsum cave in the world.
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.
Postojna Cave is a 24,340 m (79,860 ft) long karst cave system near Postojna, southwestern Slovenia. It is the second-longest cave system in the country as well as one of its top tourism sites. The caves were created by the Pivka River.
The West Virginia spring salamander is a species of troglobitic salamander in the family Plethodontidae. It is endemic to West Virginia, the United States.
Trichopetalum whitei, common name Luray Caverns blind cave millipede, is a rare troglobitic millipede of the upper Potomac River drainage in four Virginia counties and three West Virginia counties. It has been recorded from 12 caves across this range, including the Luray Caverns where it was first discovered and described.
A sump, or siphon, is a passage in a cave that is submerged under water. A sump may be static, with no inward or outward flow, or active, with continuous through-flow. Static sumps may also be connected underwater to active stream passage. When short in length, a sump may be called a duck, however this can also refer to a section or passage with some (minimal) airspace above the water.
Sistema Sac Actun is an underwater cave system situated along the Caribbean coast of the Yucatán Peninsula with passages to the north and west of the city of Tulum. Discovery of a connection to Sistema Dos Ojos in 2018 made it the longest known underwater cave system. As of January 2023, it is the second longest underwater cave system in the world, only surpassed by Sistema Ox Bel Ha.
The Pivka is a karst lost river in Slovenia. The river is 27 kilometres (17 mi) in length. The Pivka ends in Planina Cave, where it merges with the Rak River and then the Unica River. The confluence of the Pivka and the Rak is one of the largest subterranean confluences in Europe. The Pivka created Postojna Cave, the longest cave system in Slovenia as well as one of its top tourism sites.
A ponor is a natural opening where surface water enters into underground passages; they may be found in karst landscapes where the geology and the geomorphology is typically dominated by porous limestone rock. Ponors can drain stream or lake water continuously or can at times work as springs, similar to estavelles. Morphologically, ponors come in forms of large pits and caves, large fissures and caverns, networks of smaller cracks, and sedimentary, alluvial drains.
Organ Cave is a large and historic cave in Greenbrier County, West Virginia, USA. The surrounding community takes its name from the cave.
The West Virginia Speleological Survey (WVaSS) is a speleological organization and ongoing cave survey program that has gathered information and published about West Virginia caves and karst since 1967.
The Greenbrier River Watershed Association (GRWA) is one of the oldest watershed associations in the state of West Virginia, founded in 1990. It has supported the creation of other watershed associations throughout the state and maintains a policy of "upstream courtesy" and "downstream courtesy" with its neighbors.
The Butler Cave Conservation Society (BCCS) is a 501(c)(3) non-profit Virginia corporation dedicated to the conservation, exploration, survey, preservation, and scientific study of the caves and karst in and around Burnsville Cove, Virginia.
Subterranean fauna refers to animal species that are adapted to live in an underground environment. Troglofauna and stygofauna are the two types of subterranean fauna. Both are associated with hypogean habitats – troglofauna is associated with terrestrial subterranean environment, and stygofauna with all kind of subterranean waters.
Lamprechtsofen is a limestone karst river cave in Austria. With a depth of 1,632 m (5,354 ft), it is one of the deepest caves in the world. Before the discovery of the Krubera Cave in Georgia, it was the deepest-known cave in the world. Lamprechtsofen is located 2 km (1.2 mi) northwest of Weißbach bei Lofer (Salzburg), Austria, in the Leogang Mountains.
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.
Crevice Cave is a cave located in Perry County in the state of Missouri. It is the longest cave in Missouri and one of the longest caves in the United States.
Robert Gulden, nicknamed Bob, was a prominent cave surveyor and cartographer. From 1976 until his death, Gulden kept the world's best-known database of long and deep caves.
