Gough's Cave is located in Cheddar Gorge on the Mendip Hills, in Cheddar, Somerset, England. The cave is 90 metres (295 ft) deep and is 2.135 kilometres (1.33 mi) long, and contains a variety of large chambers and rock formations. It contains the Cheddar Yeo, the largest underground river system in Britain.

History

The initial sections of the cave, previously known as Sand Hole, were accessible prior to the 19th century. Between 1892 and 1898 Richard Cox Gough, who lived in Lion House in Cheddar, found, excavated and opened to the public further areas of the cave, up to Diamond Chamber, which is the end of the show cave today. Electric lighting was installed in the show caves in 1899.

The extensive flooded parts of the cave system were found and explored between 1985 and 1990.

Human remains and occupation

In 1903 the remains of a human male, since named Cheddar Man, were found a short distance inside Gough's Cave. He is Britain’s oldest complete human skeleton, having been dated to approximately 7150 BCE. There is a suggestion that the man died a violent death, perhaps related to cannibalism, although this has not been proven. Mitochondrial DNA taken from the skeleton has been found to match that of Adrian Targett, a man living in the local area today, indicating that Cheddar Man is a very distant ancestor. The remains currently reside in the Natural History Museum in London, with a replica in the Cheddar Man and the Cannibals museum in the Gorge. Other human remains have also been found in the cave.

In 2007 a carving of a mammoth, estimated to be 13,000 years old, was found in the cave.

In 2010 further human bones from the cave were examined, which ultra-filtration carbon dating dated to around the end of the ice age 14,700 years ago. A second technique, using the Alicona 3D microscope, showed that the flesh had been removed from the bones using the same tools and techniques used on animal bones. According to Professor Chris Stringer of the Natural History Museum this supports theories about cannibalism amongst the people living or visiting the cave at that time.

Access and Description

The first 820 metres (2,690 ft) of the cave are open to the public as a show cave, and this stretch contains most of the more spectacular formations. The greater part of the cave's length is made up of the river passage, which is accessible only by cave diving.

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The Wonder Cave, in Kromdraai, Gauteng, South Africa, is the third-largest cave chamber in the country, and is believed to be about 1.5 million years old. The single chamber has an area of 46000 square metres, and is 125 metres long and 154 metres wide.

It was discovered in the late 19th century by miners who dynamited and excavated limestone for the making of cement. Mining stopped during the Second Boer War, and never resumed.

The cave has about 14 stalactite and stalagmite formations up to 15 metres high, 85% of which are still growing. The 60 metre deep cave is accessible to visitors by elevator, and is located within the Rhino and Lion Nature Reserve, in the Cradle of Humankind, a World Heritage Site.

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At 15.1 kilometres (9.4 mi) long, Sof Omar Cave is the longest cave in Ethiopia; sources claim it is the longest system of caves in Africa and ranks as the 2nd longest in the World. It is situated in the Bale province in southeastern Ethiopia through which the Weyib River flows. It sinks at the Ayiew Maco entrance and reappears at the Holuca resurgence 1 kilometre (0.62 mi) away. Long a religious centre, it is sacred both to local traditional religions and to Islam. The caves are known for their many pillars, particularly in the "Chamber of Columns".

Topography

When you reach Sof Omar from Goro the scrubby bush steeply drops 90 m into a canyon. The river Web makes its way from the 4,300 metres (14,100 ft) high Bale Mountains and through a 150 kilometres (93 mi) wide outcrop of Anatole Limestone to the cave. In earlier times the river made a sharp left meander. At some point the cave dissolved a series of phreatic passages, which became big enough to capture the whole flow of the river Web. Eventually the river abandoned the meander creating a dry valley running from the cave sink at Ayiew Maco to the resurgence at Holuca. Sof Omar village is situated close to Ayiew Maco in the dry valley. Infill into the valley makes it rise to a high point of about 45 m above the Web, before it drops away to a pebble beach downstream of Holuca.

The other dominant feature is the large shakehole 100 metres (330 ft) wide and 60 metres (200 ft) deep. This is found on the basalt plateau directly above the cave.

Cave description

The cave is formed along a network of joints: one set runs approximately north to south and the other east to west. This zig-zag of passages runs in an approximate southeasterly direction. Sof Omar has 42 entrances, but generally only four are useful for gaining entrance:

Two upstream Village Entrances (one to the east and one to the west of the village)

The Tourist Entrance downstream from the Holuca Resurgence – at a point where the abandoned meander forming the dry valley rejoins the Web river

A right bank entrance downstream of Holuca accessing the Deep South part of the Clapham's Climb Series

Entering the cave via either of the Village Entrances the visitor passes a shrine used by the locals. The Ayiew Maco Series is a set of interconnecting passages of varying in width between 1m and 10m. Several can be passed through to the pebble beach on the left bank of the river. A less complex series of passages exists on the right bank. These probably connected to those on the left bank until severed by the vadose action of the Web cutting the river passage deeper.

The passage at the pebble beach is about 40 m wide – the widest passage in the cave. At the downstream end of the beach the river disappears between two columns. The way to continue is to cross the Web at Ford 1 and follow the Figure-of-Eight passage until reaching the river again at Ford 2. At this point it is possible to see down Safari Straight, the most spectacular view in the cave. The river meanders down this 15m wide, 20m high rectangular passage for 300m.

The way on involves crossing and re-crossing the river from cobble beach to cobble beach at Fords 2, 3, 4 and 5. Small passages exist on both sides. The beach after Ford 5 ends under the 50m high Great Dome. On the opposite bank a steep rise leads to Molossadie Passage. The deep, short Ford 6, Ford 7 and Ford 8 leads to a cobble beach and the entrance into the Chamber of Columns. Exiting Ford 6 on the left bank it is possible to enter the Railway Tunnel passage which offers an alternative route into Molossadie and a bypass to Fords 7 and 8 into the Chamber of Columns.

Chamber of Columns is a unique feature in the world of caves. It looks like a wide passage leaving the Web before sweeping back to the river about a 100 m downstream. The passage is circumnavigates a cluster of thick columns densely packed in the centre of chamber. The Railway Tunnel and Molossadie Passage enter the chamber from the north.

The river passage continues from the Chamber of Columns meandering for about 200m to the Big Rapids. This striking feature is formed from a jumble of huge boulders, well worn by the actions of the river. The river passage continues around a curve for about 250m before flowing around a massive boulder into the sunlight at the Holuca Resurgence. The Web continues running through a canyon. About 250m downstream the dry valley appears on the left bank.

The left side of the canyon from the resurgence to the dry valley is riddled with passages breaking out into the canyon walls, forming many of the unusable entrances to the cave. Most of these are small passages exposed as the river cut its way down. The exception to this is the 25m wide Great Hall that follows the north – south joint pattern breaking into the canyon at the resurgence. Hidden at the end of the Great Hall behind boulders is the hard-to-find Chameleon Passage. This runs along the east–west joint pattern. Some small passages lead from Chameleon to Blank Passage and back to the Big Rapids. Several small passages run from Blank Passage to Boulder Chokes.

The area surrounded by the river, Great Hall, Chameleon and Blank Passage contains a criss-cross labyrinth of passages. Two of the most significant, Bill's Passage and Tautology Passage, run between the river and the Great Hall. These are high rift passages. By climbing them it is possible to access the 35m long Balcony that overlooks the Big Rapids 7m below.

Running parallel to the Great Hall, and interconnected to it via several passages is Flintstone Passage. This splits into lots of different passages that break into the left bank of the canyon downstream of Holuca. Away from the river Flintstone runs into another of the caves' unique passages – Mudwall Passage. This passage has been filled with mud virtually to the 3m high roof. Following the infilling process a vadose trench has been cut the length of the passage revealing that the mud is formed of thin laminations.

After 200 m the Mudwall Passage enters into the small Mudwall Chamber. This has been formed by water coming from Link Passage on the west cutting across the line of the Mudwall Passage disappearing into Rimstone Passage to the east. It is this flow of water that formed the chamber. Climbing out of Mudwall Chamber leads to Batshit Passage whose floor is knee deep in guano. This leads to the large chamber, the Astrodome, which houses a large colony of bats.

Link Passage is a narrow rift passage that links back to the Chamber of Columns. A series of small passages at two levels leave Link Passage and heads towards the river passage. One of these leads into the wide Blind Passage, which also emerges into the Chamber of Columns. The upper passage is a tight crawl into the pretentiously named Wembley Stadium. This passage is formed in a fault. The survey of the British expedition in 1972 showed that the Wembley Fault extended from a right bank passage on the river, to Wembley Stadium, Mudwall and Rimstone Passages.

The Shakehole on the plateau centred on the Wembley Fault line. Obviously the fault played a significant role in the major collapse that created the Shakehole. The underground debris from the collapse forms the Big Rapids and is responsible for the boulder chokes seen near Blank Passage.

credited to wikipedia and flickr: flo142

Niah Caves is located within the district of Miri in Sarawak, Malaysia. Part of Niah National Park, the main cave, Niah Great Cave, is located in Gunung Subis and is made up of several voluminous, high-ceilinged chambers. The Great Cave lies in a large limestone block, about a kilometer long in general north to south direction and about half a kilometer wide, that is detached from the main Gunung Subis complex, by a valley between about 150 to 200 meters wide. The main Gunung Subis complex rises to about 394 meters above sea level at its highest point. The whole "Gunung Subis Limestone Complex" lies some 17 kilometers inland from the South China Sea coast and about 65 kilometers south west of the town Miri. It is roughly heart shaped measuring five kilometers from its northern tip to the south and four kilometers across. The Gunung Subis is surrounded by a low countryside with gentle hills from which the small limestone massiv and its smaller detached blocks rise rather appruptly out of the jungle, some with cliffs over 100 meters high. Though it is not an extensive cave system compared to others in Sarawak, it has been estimated to cover some 10 hectares and the roof rises to about 75 meters above the cave floor in some places. In geological terms, the limestones are part of the Subis Formation. This is dated to some 20 to 16 million years ago during the Early Miocene.

The cave is an important prehistorical site where human remains dating to 40,000 years have been found. This is the oldest recorded human settlement in east Malaysia. Painted Cave, situated in a much smaller limestone block of its own, some 150 meters from the Great Cave block's south eastern tip, has rock paintings dated as 1,200 years old. The caves are also well known for the birds' nest (Swiftlet) industry. It is a popular tourist destination in Sarawak.

Research was pioneered by Tom Harrisson in the 1950/60s. Since then local universities and foreign scientists have continued the archaeological research, and many articles have been published in the Sarawak Museum Journal. The site has been re-excavated (1999-2003+) by a joint British-Malaysian expedition to determine the accuracy of Harrisson's work.

Items found at Niah Cave include Pleistocene chopping tools and flakes, Neolithic axes, adzes, pottery, shell jewellery, boats, mats, then iron tools and ceramics and glass beads dating to the Iron Age. The most famous find is the human skull dated at around 38,000 years BCE. Painted Cave has paintings and wooden coffin 'death ships'.

Niah National Park was 31.4 km² when it was gazetted in 1974.

credited to wikipedia

The New Athos Cave (Georgian: ახალი ათონის მღვიმე), also Novoafonskaya, Novy Afon Cave, or New Afon Cave) is a karst cave in the Iverian Mountain, Georgia near New Athos. It is one of the largest caves in the world with the volume of its void of about 1,000,000 m3.

The abyss on a slope of the Iveran Mountain was known for ages, referred to as the "Bottomless Pit". It was explored in 1961 by an expedition of four: Zurab Tintilozov, Arsen Okrojanashvili, Boris Gergedava, and Givi Smyr.

Since 1975 it is a tourist attraction in Georgia, featuring its own underground railway. The cave consists of 9 major cavities.

credited to wikipedia

Crystal Cave is a cave in Kutztown, Pennsylvania, United States, the heart of Pennsylvania Dutch Country. It has been visited by millions of people since its discovery on November 12, 1871. It was found by Gideon Merkel and John Gehret. Greenwich Township farmer Samuel D. F. Kohler bought 47 acres (190,000 m2) of land, including the cave, for $5,000 in 1872. The next year he began charging 25 cents admission. The cave was used, at one time, for crop storage and dances were held in the largest room.

Some rock formations in Crystal Cave are a half-million years old. The lowest point, Devil's den, is 155 feet (47 m) below the Earth's surface and in it lives thirty to forty North American brown bats. The highest point in the cave is 65 feet (20 m) below the Earth's surface, in an area that is called "Lookout Point", for it gives a view of two-thirds of the cave. Tours are thirty to forty-five minutes long. The cave remains at 52 °F (11 °C), 54 °F (12 °C), and 56 °F (13 °C) in different areas all year round. From the main entrance of the cave to the back of the cave, it measures 500 feet (150 m) long. One rock formation is called "The Upside-down Ice Cream Cone", for the different-colored calcite deposits that look like vanilla ice cream and chocolate ice cream, along with moss and plant life that looks like mint ice cream. Also, there is an enormous drop rock that separates a room in two creating a natural bridge.

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Belum Caves is the second largest cave in Indian sub-continent and the longest caves in plains of Indian Subcontinent. Belum Caves derives its name from "Bilum" Sanskrit word for caves. In Telugu language, it is called Belum Guhalu. Belum Caves has a length of 3229 meters, making it the second largest natural caves in Indian Subcontinent. Belum Caves have long passages, spacious chambers, fresh water galleries and siphons. The caves reach its deepest point (120 feet from entrance level) at the point known as Pataalaganga.

The site

Belum Caves is located at Belum Village in Kolimigundla Mandal of Kurnool District in State of Andhra Pradesh, India. Kolimigundla is situated 3 km from Belum Caves.

Historical importance

Belum Caves are geologically and historically important caves. There are indications that Jains and Buddhists monks were occupying these caves centuries ago. Many Buddhists relics were found inside the caves. These relics are now housed in Museum at Ananthapur.

Archaeological survey of India (ASI) also found remnants of vessels, etc. of pre-Buddhist era and has dated the remnants of vessels found in the caves to 4500 BC.

Development of Caves

The caves was being used to dump wastes of nearby places till 1988. The local people of nearby areas, notably Retired Additional Superintendent of Police M. Narayana Reddy, residents of Belum Village like B. Chalapathi Reddy and others followed up Government of Andhra Pradesh to develop the caves as tourist attraction. Finally their almost two decade long efforts resulted in when Government of Andhra Pradesh declaring entire area to be protected zone. Finally in the year 1999, Andhra Pradesh Tourism Development Corporation took over the task of beautifying and maintaining the caves. APTDC sanctioned Rs.75,00,000.00 to develop the caves.

The caves are now managed by Andhra Pradesh Tourism Development Corporation (APTDC). Andhra Pradesh Tourism Development Corporation (APTDC) has developed the pathways in around 2 km of the length of the caves, provided soft illumination and has created fresh-air-shafts in the caves. At many places inside the cave, APTDC has installed bridges, staircase, etc. for easy movement inside tha cave. It has also created a canteen, washroom and toilet facilities near the entry point.

There is a giant Buddha Statue near a hillock near the Belum Caves. The area of cave known as "Meditation hall" was used by Buddhist Monks. The relics of Buddhist period were found here. These relics are now housed in museum at Ananthapur.

Main Sections of Belum Caves

*Simhadwaram — Simhadwaram means lions gate. It is a natural arch of stalactites formed in the shape of a lion’s head;

*Kotilingalu Chamber - This section contains stalactite formations which are akin to shiva lingams. This section has thousands of such stalactite giving it a surrealistic look. It has one huge pillar formed due to stalactite and stalagmite joining together.

*Patalaganga - It is a small perennial stream which disappears into the depths of the earth. This stream flows from the southeast to northwest. It disappears and is believed to be heading towards a well at the Belum village, located 2 km away from the caves.

*Saptasvarala Guha or Musical Chamber - Saptasvarala Guha means chamber of seven notes. The stalactite formations in this chamber reproduce musical sounds when these are struck with a wooden stick or knuckles. This section was opened to the public in 2006.

*Dhyan Mandir or Meditation Hall - This section is near to the entrance. An interesting formation at Meditation hall looks like a bed with pillow to recline. The local legend has it that in ancient times many sages use to live here. This section was used by Buddhist Monks. Many relics of Buddhist period were found here which are now housed in museum at Ananthapur.

*Thousand Hoods - This section has amazing stalactite formations shaped like hood of Cobra. The stalactite formations on the ceiling looks as if thousands of cobras have opened their hoods.

*Banyan Tree Hall - This section has a huge pillar with stalactites hanging from the ceiling. This gives a look of Banyan Tree with its aerial roots when seen from below. The locals call it "Voodalamari" since it looks like a Banyan Tree with its aerial roots hanging from the branches.

*Mandapam - This is a huge area inside the cave with magnificent stalactite structures on the sides giving it a look of a hall with pillars.

credited to wikipedia

Avshalom Cave (Hebrew: מערת אבשלום‎), also known as Soreq Cave or Stalactites Cave (Hebrew: מערת הנטיפים‎), is a 5,000 sq m cave in Israel, unique for its dense concentration of stalactites.

The cave was discovered accidentally in May 1968, after the use of explosives during development work, near Har-tov, 3 km east of Bet Shemesh, Israel. It is 83 m long, 60 m wide, and 15 m high.

The cave is named after Avshalom Shoam, an Israeli soldier killed in the War of Attrition. After its discovery, the location of the cave was kept a secret for several years for fear of damage to its natural treasures.

The temperature and the humidity in the cave are constant year round, and it is now open for travelers, in the heart of the Avshalom Nature Reserve.

Some of the stalactites found in the cave are four meters long, and some have been dated as 300,000 years old. Some meet stalagmites to form stone pillars.

credited to wikipedia

Abukuma-do is a limestone cave located in Fukushima Prefecture, Japan. The cave was discovered on August 15, 1969, northeast of the city of Tamura and was originally named Kamayama Shonyu-do. It was designated a natural heritage of the town on February 7, 1971 and renamed Abukuma-do on June 1, 1973. Visitors can traverse a 600-meter-long path inside the cave as well as a 120-meter-long exploration course to view the stalactites and stalagmites. Each stalactite has taken more than eighty million years to form. Beyond the public areas lie about 2,500 meters of cave that are not open to the public. Nearby Abukuma Cave is the smaller Irimizu Shonyu-do, discovered in 1927. Irimizu Limestone Cave was designated a National Natural Treasure on December 28, 1934. The temperature inside Abukuma-do is around 15°C and the humidity is above 90%.

Boxwork

A notable feature of Abukuma-do is the existence of boxwork, a rare cave formation composed of thin blades of the mineral calcite that project from cave walls and ceilings, forming a honeycomb or box-like pattern. Boxwork can also be found in Shimukugama in Okinawa and Sugawatari-do ( Ice Cross Cave) in Iwate Prefecture, but because Abukuma-do is currently the only limestone cave in Japan open to tourists, it is subsequently the only cave in Japan in which you can see boxwork.

Christmas Tree and Silver Frost

The Christmas Tree and the Silver Frost are two of the most distinctive Speleothem inside Abukuma-do. The Christmas Tree is a stalagmite and The Silver Frost meets dripstones on the roof of the cave resulting in an impressive column. Both represent a featured stop along the 600 meter course inside the cave. According to the Abukuma Caves Management Office, The Christmas Tree, at over two meters high, is said to be the largest stalagmite in the East.

credited to wikipedia

The Sudwala Caves in Mpumalanga, South Africa, are set in Precambrian dolomite rock, which was first laid down about 3800 million years ago, when Africa was still part of Gondwanaland. The caves themselves formed about 240 million years ago, making them the oldest known caves in the world.

The caves were used for shelter in prehistoric times, probably due in part to a constant supply of fresh air from an unknown source in the caves. In more modern times, the caves were discovered by Somquba, one of the sons of the Swazi king Sobhuza I, who was fleeing from his brother Mswati II. Somquba and his followers used the caves as refuge, until Somquba was killed in an unexpected attack. Survivors stayed on under the leadership of an inDuna (headman or leader) named Sudwala, thus the name.

During the Second Boer War, in 1900, the caves were used by the Boers to store ammunition for their 94-pounder Long Tom guns. It was thought that the caves may have been used by President Paul Kruger to store the legendary "Kruger Millions", gold bullion which reputedly disappeared somewhere between Waterval Onder and Nelspruit during Paul Kruger's flight from Pretoria to Lourenço Marques (now Maputo).

In 1914 a company was formed to excavate huge amounts of bat guano; this was sold as fertilizer to farmers.

The Sudwalaskraal farm that is home to the caves was purchased in 1965 by Philippus Rudolf Owen, and he opened the caves as a tourist attraction.

The major chamber in the Sudwala Caves is the P. R. Owen Hall; it is 70 metres in diameter and 37 metres high, with a constant temperature of 17°C. This chamber was used as a concert hall on a number of occasions, including July 1970, when the Russian singer Ivan Rebroff gave a concert. Concerts were stopped due to vandalism in the caves in 2002, but were started again in 2006.

There are a number of calcium structures in the cave, known by names such as the "Lowveld Rocket", "Samson's Pillar", and the "Screaming Monster"; some have been dated to 200 million years old. There are also microbial fossils of a cyanobacterium known as collenia in the rock; these formed 2000 million years ago.

The Sudwala Caves are a popular tourist attraction in Mpumalanga, and are next to the P R Owen Dinosaur Park. One-hour tours of the cave are run during the day, and a monthly five-hour-long "Crystal Tour" takes adventurous visitors 2000 metres through the cave, with the tour culminating at a crystal chamber that bears aragonite crystals.

credited to wikipedia

Lechuguilla Cave is, as of August 2007, the fifth longest cave (126.1 miles (203 km)) known to exist in the world, and the deepest in the continental United States (1,604 feet (489 m)), but it is most famous for its unusual geology, rare formations, and pristine condition.

The cave is named for Agave lechuguilla, a plant found near its entrance. It is located in Carlsbad Caverns National Park, New Mexico. Access to the cave is limited to approved scientific researchers, survey and exploration teams, and National Park Service management-related trips.

Exploration history

Lechuguilla Cave was known until 1986 as a small, fairly insignificant historic site in the park's backcountry. Small amounts of bat guano were mined from the entrance passages for a year under a mining claim filed in 1914. The historic cave contained a 90-foot (27 m) entrance pit known as Misery Hole, which led to 400 feet (122 m) of dry dead-end passages.

The cave was visited infrequently after mining activities ceased. However, in the 1950s cavers heard wind roaring up from the rubble-choked floor of the cave. Although there was no obvious route, different people concluded that cave passages lay below the rubble. A group of Colorado cavers gained permission from the National Park Service and began digging in 1984. The breakthrough, into large walking passages, occurred on May 26, 1986.

Since 1986, explorers have mapped over 126 miles (203 km) of passages and have pushed the depth of the cave to 1,604 feet (489 m), ranking Lechuguilla as the 5th longest cave in the world (4th longest in the United States) and the deepest limestone cave in the country. Cavers, drawn by the caves' pristine condition and rare beauty, come from around the world to explore and map its passages and geology.

Geology

Lechuguilla Cave offered even more than just its extreme size. Cavers were greeted by large amounts of gypsum and lemon-yellow sulfur deposits. A large variety of rare speleothems, some of which had never been seen anywhere in the world, included 20 feet (6.1 m) gypsum chandeliers, 20 feet (6.1 m) gypsum hairs and beards, 15 feet (4.6 m) soda straws, hydromagnesite balloons, cave pearls, subaqueous helictites, rusticles, U-loops and J-loops. Lechuguilla Cave surpassed its nearby sister, Carlsbad Caverns, in size, depth, and variety of speleothems, though no room has been discovered yet in Lechuguilla Cave which is larger than Carlsbad's Big Room.

Scientific exploration has been conducted as well. For the first time a Guadalupe Mountains cave extends deep enough that scientists may study five separate geologic formations from the inside. The profusion of gypsum and sulfur lends support to speleogenesis by sulfuric acid dissolution. The sulfuric acid is believed to be derived from hydrogen sulfide which migrated from nearby oil deposits. Thus, this cavern (as well as Carlsbad Caverns) apparently formed from the bottom up, in contrast to the normal top-down carbonic acid dissolution mechanism of cave formation.

Rare, chemolithoautotrophic bacteria are believed to occur in the cave. These bacteria feed on the sulfur, iron, and manganese minerals and may assist in enlarging the cave and determining the shapes of some unusual speleothems. Other studies indicate that some microbes may have medicinal qualities that are beneficial to humans.

Lechuguilla Cave lies beneath a park wilderness area. However, it appears that the cave's passages may extend out of the park into adjacent Bureau of Land Management (BLM) land. A major threat to the cave is proposed gas and oil drilling on BLM land. Any leakage of gas or fluids into the cave's passages could kill cave life or cause explosions.

credited to wikipedia

Mammoth Cave National Park is a U.S. National Park in central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. The official name of the system is the Mammoth-Flint Ridge Cave System for the ridge under which the cave has formed. The park was established as a national park on July 1, 1941. It became a World Heritage Site on October 27, 1981, and an international Biosphere Reserve on September 26, 1990.

The park's 52,830 acres (214 km²) are located primarily in Edmonson County, Kentucky, with small areas extending eastward into Hart County and Barren County. It is centered around the Green River, with a tributary, the Nolin River, feeding into the Green just inside the park.

Limestone labyrinth

Mammoth Cave developed in thick Mississippian-aged limestone strata capped by a layer of sandstone, making the system remarkably stable. It is known to include more than 360 miles (580 kilometers) of passageway; new discoveries and connections add several miles to this figure each year. Mammoth Cave National Park was established to preserve the cave system.

The upper sandstone member is known as the Big Clifty Sandstone: thin, sparse layers of limestone interspersed within the sandstones give rise to an epikarstic zone, in which tiny conduits (cave passages too small to enter) are dissolved by the natural acidity of groundwater. The epikarstic zone concentrates local flows of runoff into high-elevation springs which emerge at the edges of ridges. The resurgent water from these springs typically flows briefly on the surface before sinking underground again at elevation of the contact between the sandstone caprock and the underlying massive limestones. It is in these underlying massive limestone layers that the human-explorable caves of the region have naturally developed.

The limestone layers of the stratigraphic column beneath the Big Clifty, in increasing order of depth below the ridgetops, are the Girkin Formation, the St. Genevieve Limestone, and the St. Louis Limestone. For example, the large Main Cave passage seen on the Historic Tour is located at the bottom of the Girkin and the top of the St. Genevieve Formation.

Each of the primary layers of limestone are divided further into named geological units and subunits. One area of cave research involves correlating the stratigraphy with the cave survey produced by explorers. This makes it possible to produce approximate three-dimensional maps of the contours of the various layer boundaries without the necessity for test wells and extracting core samples.

The upper sandstone caprock is relatively hard for water to penetrate: the exceptions are where vertical cracks occur. This protective role means that many of the older, upper passages of the cave system are very dry, with no stalactites, stalagmites, or other formations which require flowing or dripping water to develop.

However, the sandstone caprock layer has been dissolved and eroded at many locations within the park, such as the Frozen Niagara room. The "contact" between limestone and sandstone can be found by hiking from the valley bottoms to the ridgetops: typically, as one approaches the top of a ridge, one sees the outcrops of exposed rock change in composition from limestone to sandstone at a well-defined elevation.

At one valley bottom in the southern region of the park, a massive sinkhole has developed. Known as "Cedar Sink," the sinkhole features a small river entering one side and disappearing back underground at the other side.

Mammoth Cave is home to the endangered Kentucky cave shrimp, a sightless albino shrimp.

Biology and ecosystem

The bats that inhabit the caverns are the following: Indiana bat (Myotis sodalis), Gray bat (Myotis grisescens), Little brown bat (Myotis lucifugus), Big brown bat (Eptesicus fuscus), and the Eastern pipistrelle bat (Pipistrellus subflavus).

All together, these and more rare bat species such as the Eastern Small-footed Bat had estimated populations of 9-12 million just in the Historic Section. While these species still exist in Mammoth Cave, their numbers are now no more than a few thousand at best. Ecological restoration of this portion of Mammoth Cave, and facilitating the return of bats, is an ongoing effort. Not all bat species here inhabit the Cave; the red bat (Lasiurus borealis) is a forest-dweller, found underground only rarely.

Other animals which inhabit the caves include: two genera of Crickets (Hadenoecus subterraneus) and (Ceuthophilus stygius) (Ceuthophilus latens), a Cave salamander (Eurycea lucifuga), two genera of Eyeless Cave Fish (Typhlichthys subterraneus) and (Amblyopsis spelaea), a Cave Crayfish (Orconectes pellucidus), and a Cave Shrimp (Palaemonias ganteri)

In addition, some surface animals may take refuge in the entrances of the caves but do not generally venture into the deep portions of the cavern system.

credited to wikipedia and flickr: Morland Smith

The Eisriesenwelt (German for "World of the Ice Giants") is a natural limestone ice cave located in Werfen, Austria, about 40 km south of Salzburg. The cave is inside the Hochkogel mountain in the Tennengebirge section of the Alps. It is the largest ice cave in the world, extending more than 42km and visited by about 200,000 tourists every year.

Geology

The Tennengebirge mountains were formed during the late Tertiary period, during the Würm glaciation period of the Pleistocene. The mountain range, one of the massifs in the Austrian Alps, is the largest karst plateau in the Salzburger Alps, and the Eisriesenwelt is located at the rim of this plateau. Although the cave has a length of 42 km, only the first kilometer, the area that tourists are allowed to visit, is covered in ice. The rest of the cave is formed of limestone.

Eisriesenwelt was formed by the Salzach river, which eroded passageways into the mountain. The ice formations in the cave were formed by thawing snow which drained into the cave and froze during winter.

Since the entrance to the caves is open year-round, chilly winter winds blow into the cave and freeze the snow inside. In summer, a cold wind from inside the cave blows toward the entrance and prevents the formations from melting.

History

The first official discovery of Eisriesenwelt was by Anton Posselt, a natural scientist from Salzburg, in 1879, though he only explored the first two hundred meters of the cave. Before his discovery, the cave was known only to locals, who, believing that it was an entrance to Hell, refused to explore it. In 1880, Posselt published his findings in a mountaineering magazine, but the report was quickly forgotten.

Alexander von Mörk, a speleologist from Salzburg, was one of the few people who remembered Posselt's discovery. He led several expeditions into the caves beginning in 1912, which were soon followed by other explorers. Von Mörk was killed in World War I in 1914, and an urn containing his ashes is inside a niche in the cave. In 1920, a cabin for the explorers, Forscherhütte, was built and the first routes up the mountain were established. Tourists began to arrive soon after, attracted by the cave's sudden popularity.

Later another cabin, the Dr. Oedl House, and paths from Werfen and Tänneck were constructed.

In 1955 a cable car was built, shortening the 90-minute climb to 3 minutes. Today the Eisriesenwelt cave is owned by the National Austrian Forest Commission, which has leased it to the Salzburg Association of Cave Exploration since 1928. The Forest Commission still receives a percentage of the entrance fees.

Visiting

The cave is open from May 1st to October 26th every year. Its operating hours are 9:00 a.m. to 4:30 p.m. in July and August and 9:00 a.m. to 3:30 p.m. in May/June and September/October. Temperatures inside the cave are usually below freezing, and warm clothing is recommended. Photography is not permitted once visitors are inside the cave.

The tour begins at the entrance to the cave, and continues inwards to Posselt Hall, a large room with a stalagmite called Posselt Tower in the centre. Past the Posselt Tower, one encounters an ashen cross on the wall of the cave, marking the farthest point of exploration of Anton Posselt. From there one can see the Great Ice Embankment, a massive formation that rises to a height of 25 metres and represents the area of greatest ice growth. Next is Hymir's Castle, named after a giant in Norse mythology. Here stalactites create a formation called Frigga's Veil, or the Ice Organ.

Next on the tour is the Alexander von Mörk Cathedral, one of the largest rooms in the cave and the final resting place of von Mörk's ashes. The final stop on the tour is the Ice Palace, a kilometre into the cave and 400 metres underground. From here, visitors must turn around and walk back through the caves to reach the entrance. The round-trip tour through the cave takes around one hour and 15 minutes.

credited to wikipedia and flickr: MG007