Jenolan Caves

Jenolan Caves are caves in the Blue Mountains, New South Wales, Australia; 175 kilometres west of Sydney. They are the most celebrated of several similar groups in the limestone of the country being the oldest discovered open caves in the world. They include numerous Silurian marine fossils of great interest and the calcite formations, sometimes pure white, are of extraordinary beauty. The cave network is enormous - over 40 km of multi-level passages - still undergoing active exploration. Several kilometres of the caves have been rendered easily accessible to paying visitors and are well lit.
By measuring the ratio of radioactive potassium and trapped argon gas, which was produced when the potassium decayed, scientists determined the age of the clay in the cave to be approximately 340 million years old, thereby making this cave complex the world's oldest known and dated open cave system. The Commonwealth Scientific and Industrial Research Organisation (CSIRO) in association with the University of Sydney and the Australian Museum lead the efforts in scientific research into the caves.

Jenolan Caves - Nettle Cave
Nettle Cave
Jenolan Caves - Orient Cave
Orient Cave
Jenolan Caves - River Cave
River Cave

Local Gundungarra tribes knew Jenolan Caves area as 'Binoomea' (Dark Places) and possibly shunned them; in approximately 1835-40 the area was recorded for the first time by either James, Charles or Alf Whalan, three brothers who each claimed to have discovered the caves while searching for a bushranger, James McKeown, whom they claimed used the caves as a hide-out. One of the less-visited caverns in the area is called McKeown's Hole, however there is no actual evidence of his existence. It is more likely the brothers were searching for cattle that had strayed from their nearby farm.
One theory is that the name "Jenolan" is said to come from "Genowlan", the Aboriginal name for a local mountain peak. Another theory is that is derived from the name of an early settler, J. Nolan.
The caves, then known as the Fish River Caves, came under New South Wales Government control in 1866, becoming only the second area in the world reserved for the purpose of conservation and the following year Jeremiah Wilson was appointed as the first "Keeper of the Caves". Wilson not only explored the already known Elder and Lucas Caves but later discovered the Imperial, Left Imperial (now known as Chifley), Jersey and Jubilee Caves. The caves were open to tourism early, but there was little protection from visitors damaging formations until souveniring was banned in 1872. In 1884 the name Jenolan Caves was adopted, an Aboriginal name meaning 'high place' as it is named after Mount Jenolan nearby.
The road to the caves originally went in from Tarana, which meant that travellers from the south had to take a long, roundabout route of about 90 miles from Katoomba to Oberon, and, from there, to Tarana.
In the mid-1880s, hotel keepers in Katoomba wanted to improve business by constructing a road to the Caves from their town, but the steep, rough ground between the caves and town was a major obstacle, and several attempts failed. However, representations were made to the state premier by Peter Fitzpatrick of Burragorang, who was connected to some mining operations near Katoomba.
In April, 1884, William Marshall Cooper, Surveyor of Public Parks for the State Government, was assigned the job, and worked out a horse-and-carriage track in a 10-day trek from Katoomba to the Caves. The route was, he remarked, 26.5 miles from the Western Hotel in Katoomba. "... Anyone accustomed to walking can do it comfortably in 12 hours... when the proposed horse track is completed, it will be a very enjoyable ride of five hours." It became known as the Six Foot Track.
Cooper also pointed out that "Fish River Caves" was a misnomer, the Fish River being on the western side of the Dividing Range and the caves on the eastern side. At his suggestion, the caves were officially named "Jenolan Caves" in 1884 after the parish in which they are situated.
By 1885, Parliament had approved ₤2,500 for the construction of Cooper's bridle track, with the work starting at the most difficult area, the Megalong Cleft, where a zig-zag had to be cut, partly in solid rock, to reduce the grade to 1:5.5.
The first recorded passage of the completed bridle track from Katoomba to Jenolan was by the governor, Lord Carrington, in September 1887. Lord Carrington also made the first official visit to the caves at the completion of his journey, accompanied by Wilson.
In 1898 the current Caves House guesthouse was built, replacing the earlier wooden accommodation house built by Jeremiah Wilson, which had been destroyed in a fire.
James Wiburd become "Keeper of the Caves" in 1903 and quickly discovered five more caves within eighteen months: the River, Pool of Cerberus, Temple of Baal, Orient and Ribbon Caves. He remained Keeper until 1932, when he left following a bitter dispute over the development of the Ribbon Cave for tourism.
The Chifley Cave, originally known as the Left Imperial Cave but named for Prime Minister Ben Chifley in 1952, was the first of the caves to be lit with electric light, as early as 1880. In 1968, the Orient Cave became the first in the world to be cleaned, due to contamination from a nearby coal boiler. This was entering the cave via a new tunnel blasted 400 feet through to the Orient cave in the 1950s to allow easier access (entering at Bat End). Steam cleaning was found to be damaging to the crystal formations, due to the rapid expansion and contraction caused by the heat from the steam, and these days water from the caves' own underground rivers is used if cave cleaning becomes necessary.

Source: Wikipedia