58 Fun Facts About Caves

Most of the world's caves are formed by the slow dissolving of which rock?

Limestone (calcium carbonate) dissolves in rainwater charged with carbonic acid, which eats along cracks and bedding planes; the resulting sinkhole-pocked landscape is called karst.

What is the name for the scientific study of caves?

Speleology is the science; recreational exploration is caving, potholing or spelunking, and the name was coined by Émile Rivière in 1890.

What is the cave formation that grows up from the floor beneath a stalactite called?

A stalagmite builds up from the floor where drips land; the mnemonic is that stalactites hold tight to the ceiling and stalagmites might reach it.

Which cave system in Kentucky has the greatest total length of surveyed passage of any in the world, over 675 km?

Mammoth Cave, a national park since 1941 and a World Heritage Site since 1981, has more than 675 kilometres of mapped passage, far ahead of any other known cave.

In which country is Sơn Đoòng, the cave with the largest known passage in the world?

Sơn Đoòng, in Vietnam's Phong Nha-Kẻ Bàng National Park, was found in 1990 by a local man searching for agarwood; he did not return with cavers until 2009.

Bracken Cave near San Antonio, Texas, is the summer home of the largest colony of which animals on Earth?

An estimated 20 million Mexican free-tailed bats roost there from March to October, the largest known concentration of mammals anywhere.

Waitomo Cave in New Zealand is famous for a ceiling lit by thousands of what?

Waitomo's glowworms are the larvae of a fungus gnat found only in New Zealand, dangling sticky silk threads to snare prey drawn to the light.

What are cave visitors told to do to enter the Blue Grotto on the island of Capri?

The entrance is barely a metre high, so boatmen have passengers lie flat in a small rowboat and pull through on a chain; Tiberius used the cave as a private swimming pool.

In 2018, twelve boys and their football coach were trapped for over two weeks in the Tham Luang cave in which country?

The Wild Boars were trapped in Thailand's Tham Luang Nang Non cave from 23 June 2018; two British divers found them about four kilometres in, and all thirteen were sedated and dived out on 8-10 July.

The Paleolithic paintings of Lascaux, with its Hall of the Bulls, are in which country?

France's Lascaux cave was found in 1940 by an 18-year-old whose dog investigated a hole left by an uprooted tree; the original cave has been closed since 1963.

Which site in the Altai Mountains of Siberia gave its name to an extinct human species identified from a finger bone in 2010?

Denisova Cave's finger bone yielded the Denisovan genome in 2010; the site later produced a 50,000-year-old bone needle and 'Denny', a girl with a Neanderthal mother and Denisovan father.

Fingal's Cave, whose echoes inspired Mendelssohn's Hebrides Overture, is a sea cave on which Scottish island?

Fingal's Cave is on the uninhabited isle of Staffa, off Mull; its hexagonal basalt columns match the Giant's Causeway, and Turner painted it in 1832.

Cave-dwelling animals such as blind fish and pale salamanders that cannot live outside caves are called what?

Troglobites are obligate cave-dwellers; species that merely visit, such as bats that feed outside, are trogloxenes, and those that can live in or out are troglophiles.

Which blind, pale cave salamander, nicknamed the 'human fish', can survive years without eating?

The olm (Proteus anguinus), once taken for a dragon's offspring when floods washed it out, averages about 68 years of life and can go a decade without food.

The Cave of Altamira, the first cave whose paintings were recognised as prehistoric, is in which country?

Altamira, in Cantabria, northern Spain, was recognised in 1879 by Marcelino Sanz de Sautuola, who was accused of forgery; its Polychrome Ceiling bison now form Cantabria's tourism logo.

The word "karst", for landscapes of sinkholes and underground drainage, is associated with a plateau in which country?

The Kras (Karst) plateau of south-western Slovenia gave the landscape its name; Slovenia's Postojna Cave has run a tourist train since 1872, with 5 of its 24 kilometres open.

What are the mineral formations inside caves, from stalactites to flowstone, collectively called?

Speleothems (Greek for 'cave deposits') are almost all calcite or aragonite; their growth layers can be read like tree rings as records of past climate.

Lechuguilla Cave and Carlsbad Cavern in New Mexico were carved from below by what, formed from gas rising off oil deposits?

Sulfuric acid formed when hydrogen sulfide mixed with groundwater and ate upward; most caves are dissolved from above by rainwater.

Kazumura Cave on the slopes of Kīlauea in Hawaii is the world's longest and deepest example of what kind of cave?

Kazumura is a lava tube in the ʻAilāʻau flow that erupted around 500 years ago; it runs about 65 kilometres and drops 1,100 metres.

The Cave of the Crystals beneath the Naica mine in Mexico holds beams up to 11 metres long of which mineral?

The beams are selenite, a crystalline form of gypsum, grown over hundreds of thousands of years in mineral-rich water at a steady 58 °C; unprotected visitors can last only minutes.

The Sarawak Chamber, the largest cave room by area, lies in Gunung Mulu National Park on which island?

Gunung Mulu lies in Sarawak, the Malaysian part of Borneo; three visiting cavers found the chamber in 1981 and judged it far larger than Carlsbad's Big Room, then the record-holder.

Which Ardèche cave, found in 1994, is the subject of Herzog's 'Cave of Forgotten Dreams'?

Chauvet, found by Jean-Marie Chauvet and two companions in December 1994, is closed to the public; Herzog was allowed six four-hour shooting days by the culture ministry.

Cueva de las Manos, a UNESCO site of stencilled hands, is in which country?

Cueva de las Manos lies in Argentina's Santa Cruz province, in Patagonia; the artists sprayed pigment through bone pipes, and radiocarbon dates on those pipes helped date the work.

Krubera and Veryovkina, the first two caves explored below 2,000 metres, are in which mountain range?

Both lie in the Arabika Massif of the Western Caucasus, in Abkhazia; Krubera is also called Voronya, 'crows' cave', after the birds nesting in its entrance pit.

Rising Star Cave in South Africa's Cradle of Humankind yielded fossils of which hominin species, announced in 2015?

Homo naledi, announced in September 2015, was recovered from the Dinaledi Chamber, reached through 'Superman's Crawl', passable only with one arm stretched ahead, and the 'Chute'.

Derinkuyu, an underground city carved into soft volcanic tuff and able to shelter 20,000 people, is in which region of Turkey?

Derinkuyu lies in Cappadocia, in central Anatolia's Nevşehir province; its name means 'deep well', and the complex could be sealed from inside with rolling stone doors.

The Wookey Hole caves in Somerset are used by a local dairy to mature which food?

The caves hold a steady 11 °C; the same show cave houses a human-shaped rock formation known as the Witch of Wookey.

Movile Cave in Romania, sealed off for 5.5 million years, hosts an ecosystem based entirely on what?

Movile's food web rests on chemosynthesis: bacteria oxidising hydrogen sulfide and methane in air that is rich in sulfide and carbon dioxide but poor in oxygen.

The Jenolan Caves west of Sydney claim what world record?

Clay in Jenolan's caves was dated in 2006 to about 340 million years, making it the oldest known open cave system; the network follows the underground Jenolan River.

Cenotes, the water-filled sinkholes used by the Maya for water and sacrifice, are concentrated on which peninsula?

A dense ring of Yucatán cenotes traces the buried rim of the Chicxulub impact crater; the Maya used them for water supplies and occasionally for sacrificial offerings.

Cave bears, which died out around 24,000 years ago, differed from brown bears mainly in what way?

Their bones were first described in 1774, when scholars thought they might be dragons or unicorns.

Which cave near Werfen in Austria is the largest ice cave in the world?

Eisriesenwelt, 'world of the ice giants', runs 42 kilometres into the Tennengebirge near Werfen; only its first kilometre is iced, by snowmelt freezing inside.

Gough's Cave, where the UK's oldest complete human skeleton was found in 1903, opens onto which Somerset landform?

Gough's Cave opens at the foot of Cheddar Gorge; Cheddar Man, dated to about 10,000 years ago, was found there in 1903, and the Cheddar Yeo river emerges from the cave.

Puerto Princesa's underground river, voted one of the New 7 Wonders of Nature in 2012, flows beneath which Philippine island?

The river runs about 8 kilometres beneath the Saint Paul range on Palawan before meeting the sea; a 2010 expedition found a second level with small waterfalls.

The Batu Caves near Kuala Lumpur, with a 43-metre statue at the foot of the steps, are the focus of which Hindu festival?

Thaipusam brings vast processions of Hindu devotees up the 272 steps to the Murugan temple at Batu Caves; Chinese settlers had dug guano there in the 1860s before the temple's founding in 1891.

Ruby Falls, a 145-foot waterfall inside a cave under Lookout Mountain, is in which city?

Leo Lambert found Ruby Falls in 1928 while drilling an elevator shaft toward Lookout Mountain Cave, whose natural entrance had been sealed; the cave lies under Chattanooga, Tennessee.

The largest known cave room by volume, the Miao Room, is in which country?

The Miao Room, in the Gebihe system in Guizhou, China, was laser-scanned in 2013 at about 10.8 million cubic metres, edging out the Sarawak Chamber, the largest by floor area.

Roughly how deep below the surface can any cave exist before the weight of overlying rock crushes it shut?

That limit is vertical depth beneath the ground; a cave's measured depth from entrance to lowest point can be less constrained.

Which speleothem grows in curling, gravity-defying shapes thanks to capillary forces?

Helictites twist against gravity because water is drawn through a tiny central canal by capillary action; Timpanogos Cave in Utah has one of the largest collections, nicknamed butterflies and curly-fries.

In caving, what is a passage flooded to the ceiling, forcing a dive, called?

A sump is a passage flooded to the roof, passable only by diving; a 'duck' still leaves an airspace, and an aven is a shaft leading upward.

Which enslaved guide mapped and named many features of the world's longest cave in the 1840s and 1850s?

Stephen Bishop, enslaved and brought to the cave as a guide in 1838, crossed the Bottomless Pit that year and drew from memory the 1842 map that charted much of the system.

Which teenager explored Carlsbad Cavern with a homemade wire ladder in 1898 and named its Big Room?

Jim White, a 16-year-old cowboy, climbed down with a wire ladder in 1898 after seeing bats pour from the entrance; he named the Big Room, nearly 1,220 metres long.

What name did divers give the 13,000-year-old girl's skeleton found in Hoyo Negro, Mexico?

Naia, named for a water nymph, was a teenager whose skeleton lay in the Hoyo Negro pit of the Sac Actun system; her genome tied her to today's Native Americans.

The Jeita Grotto, home to the world's largest known stalactite, supplies drinking water to more than a million people in which country?

Jeita, in the Nahr al-Kalb valley 18 km north of Beirut, Lebanon, has a lower river cave visited by boat and upper galleries found in 1958, sixty metres above.

The Reed Flute Cave, lit in lurid colours and inscribed with Tang-dynasty poems, is a landmark of which Chinese city?

Reed Flute Cave, in Guilin, Guangxi, takes its name from reeds at its mouth once made into flutes; refugees fleeing Japanese troops rediscovered it in the 1940s.

Which grotto near Mecca is revered by Muslims as the place where Muhammad received his first revelation of the Quran?

The Cave of Hira sits on Jabal al-Nour, the Mountain of Light, about 4 kilometres from the Kaaba; Muslims hold that Gabriel first recited the Quran to Muhammad there during Ramadan.

The Cave of the Apocalypse, where St John is said to have received the visions of Revelation, is on which Greek island?

Patmos's cave sits halfway up the mountain between the villages of Chóra and Skala; UNESCO listed it in 1999 together with the Monastery of Saint John the Theologian.

Which former navy diver died delivering air tanks during the 2018 Tham Luang rescue?

Saman Kunan, a retired Navy SEAL who had volunteered, ran out of air returning through the flooded passages in the early hours of 6 July 2018.

Which farmer was lowered into the Cango Caves' first hall, which bears his name, in 1780?

Jacobus Van Zyl, a local farmer, was lowered into the first chamber in 1780; Van Zyl's Hall is about 98 metres long, and only a quarter of the 4-kilometre system is open.

Roughly how deep is Fantastic Pit in Ellison's Cave, Georgia?

Fantastic Pit drops 586 feet (179 m), the deepest known free-fall pit in the continental United States; its neighbour Incredible Pit drops another 440 feet.

The largest chamber in any show cave, the Salle de la Verna, is in which mountain range?

The Salle de la Verna, in the Pierre Saint-Martin system of the French Pyrenees, opened to visitors in 2010; its 194-metre height dwarfs any other chamber you can walk into on a tour.

The highest surveyed cave in the world, Qaqa Mach'ay, sits at nearly 5,000 metres in which mountains?

Later GPS readings suggest even that altitude is understated.

The Sarawak Chamber was discovered in January 1981 by three cavers from which country?

Britain's Andy Eavis, Dave Checkley and Tony White found it on the Mulu '80 expedition; a laser scan in 2011 confirmed it as the largest chamber by area.

Sof Omar, sacred to Muslims and to Oromo traditional religion, is the longest cave in which country?

Sof Omar, in Ethiopia's Bale zone, is carved by the Weyib River, which sinks at one entrance and reappears a kilometre away; a 1972 survey made it Africa's longest known cave.

The Longyou Caves, 24 huge hand-carved sandstone chambers of unknown origin, were found in 1992 by farmers doing what?

Five ponds turned out to be flooded caverns more than 2,000 years old, unmentioned in any historical record.

What term do speleologists reserve for a hollow formed within moving ice, as opposed to a rock cavern that holds year-round ice?

A glacier cave is a hollow inside moving glacier ice; 'ice cave' properly means a rock cave holding year-round ice, though the term is often misapplied to glacier caves.

What led cavers Gary Tenen and Randy Tufts to Kartchner Caverns, Arizona, in 1974?

Tenen and Tufts squeezed through a narrow crack at the bottom of a sinkhole after feeling warm, moist air rising from it; they kept the cave secret for 14 years.

Tulum and the flooded cave systems around it lie in which Mexican state?

Tulum sits on the Caribbean coast of Quintana Roo, the state that covers the eastern Yucatán Peninsula and holds the world's longest underwater cave systems.