Brunette Girl With Blue Eyes Posing On Rocks In A Small Cave

• The cave system with the greatest total length of surveyed passage is Mammoth Cave (Kentucky, USA) at 628 kilometres (390 mi) in length. This record is unlikely to be surpassed in the near future, as the next most extensive known cave is Jewel Cave near Custer, South Dakota, at 242 kilometres (150 mi).
• The longest surveyed underwater cave is Sistema Sac Actun in Yucatán, Mexico at 215 km (134 mi). The record has been exchanged several times with Sistema Ox Bel Ha, currently at 182 kilometres (113 mi).
• The deepest known cave (measured from its highest entrance to its lowest point) is Voronya Cave (Abkhazia), with a depth of 2,191 metres (7,188 ft). This was the first cave to be explored to a depth of more than 2 kilometres (1.2 mi). (The first cave to be descended below 1 kilometre (0.62 mi) was the famous Gouffre Berger in France.) The Illyuzia-Mezhonnogo-Snezhnaya cave in Abkhazia, (1,753 metres or 5,751 feet) and the Lamprechtsofen Vogelschacht Weg Schacht in Austria (1,632 metres or 5,354 feet) are the current second- and third-deepest caves. The deepest cave record has changed several times in recent years.
• The deepest vertical shaft in a cave is 603 metres (1,978 ft) in Vrtoglavica Cave in Slovenia. The second deepest is Patkov Gušt at 553 metres (1,814 ft) in the Velebit mountain, Croatia.