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

Records and superlatives
• 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).