The Gouffre Gros Gadeau is an active water shaft cave where you can descend a good 110 meters. Eight small shafts between 16 and 6 meters deep first have to be abseiled and then climbed again and the whole thing next to or in the waterfalls. . Depending on the weather, the cave in the lower area is very dangerous. When it rains or snow melts, the water rises quickly and floods the flat and narrow passages.