(See: Amazing 3-D Tour of a Chinese Supercave.) The expedition first mapped the chamber with extensive laser scanning surveys in 2013. To make the new size estimate, the team reprocessed the results with experts from the U.K.'s University of Lancaster to yield more precise measurements of the cavern.
http://news.nationalgeographic.com/news/2014/09/140927-largest-cave-china-exploration-science/
(Related: China's Supercave.) A laser-mapping expedition funded by the National Geographic Society reported the new measurement at the United Kingdom's national caving conference in Leek this weekend.
http://news.nationalgeographic.com/news/2014/09/140927-largest-cave-china-exploration-science/
As a result of the growing renown of Mammoth Cave, the cave boasted famous visitors such as actor Edwin Booth (his brother, John Wilkes Booth, assassinated Abraham Lincoln in 1865), singer Jenny Lind (who visited the cave on April 5, 1851), and violinist Ole Bull who together gave a concert in one of the caves.
https://en.wikipedia.org/wiki/Mammoth_Cave_National_Park
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.
https://en.wikipedia.org/wiki/Mammoth_Cave_National_Park
For all its magnitude, it should be remembered that Mammoth Cave is only one of many large caves in Kentucky. Kentucky is home to another 14 of the longest caves in the world. Prior to 1983, it was 3, but the 50 mile (80 km) long Roppel Cave System was connected to Mammoth Cave and removed from the list. The Fisher Ridge cave system currently ranks seventh on the world list, with a total length of 112 miles (180 km).
http://www.uky.edu/KGS/education/mammothcave.htm
More than 367 miles (591 km) of passages have been mapped. To get an idea of how long Mammoth Cave is, you should consider that the second longest cave in the world, Optimisticeskay Cave, in the Ukrainskaya region of the C.I.S. (former Soviet Union), is only 143 miles (230 km) long. Mammoth Cave is three times longer than its nearest competitor.
http://www.uky.edu/KGS/education/mammothcave.htm
Photograph by Carsten Peter, National Geographic China's immense Miao Room cavern, hidden beneath rolling hills and reachable only by an underground stream, is the world's biggest cave chamber, an international mapping team reported on Sunday. (Related: China's Supercave..
http://news.nationalgeographic.com/news/2014/09/140927-largest-cave-china-exploration-science/
The Miao Room volume measurement exceeds Sarawak Chamber in Malaysia, the past title-holder, by about 10 percent. But the Malaysian cavern is still the world’s largest by surface area, with some 1.66 million square feet (154,500 square meters) of expanse.
http://news.nationalgeographic.com/news/2014/09/140927-largest-cave-china-exploration-science/
It is centered on the Green River, with a tributary, the Nolin River, feeding into the Green just inside the park. With 400 miles (640 km) of surveyed passageways Mammoth Cave is by far the world's longest known cave system, being over twice as long as the second-longest cave system, Mexico 's Sac Actun underwater cave.
https://en.wikipedia.org/wiki/Mammoth_Cave_National_Park
MORE... Picture: John Spies/Barcroft Media. At more than 200m high, 150m wide and 5km long, the Hang Son Doong cave in Vietnam is so big it has its own river, jungle and climate. Australian photographer John Spies, 59, spent a week photographing the natural wonder of the cave system.
http://www.telegraph.co.uk/news/picturegalleries/earth/10914205/In-pictures-Inside-Hang-Son-Doong-the-worlds-largest-caves-in-Vietnam.html
the longest cave in the world
The longest cave in the world is in Kentucky.