Gouffre Berger Cave, Engins, Vercors Plateau, French Prealps, France

To return from the bottom of the cave back to the surface can take between 15 and 30 hours, without long breaks. In 1967, Ken Pearce, a metallurgy teacher from Britain, descended with the Pegasus caving club team from Nottingham UK, organised and led by Peter Watkinson, and along with a 40-metre (130 ft) dive, reached a depth of 1,133 metres (3,717 ft). They emerged after 13 days underground, having set a new world record at the time.
In 1968, B Leger and J Dubois reached a depth of −1,141 metres (−3,743.4 ft). This record was held until July 1982, when Patrick Penez attained −1,191 metres (−3,907.5 ft). In recent years there have been six fatalities in this cave, five due to water. During a storm or heavy rain, the Gouffre Berger can become a dangerous trap, and the water levels rise very quickly. In 1996, Englishwoman Nicole Dollimore and Hungarian Istvan Torda died due to violent flooding in the cave.