Gournier Cave, Underground river cave in Vercors Massif, France

Gournier Cave is a cave system with an underground river flowing through limestone formations in the Vercors Massif. The cave contains a lake at its entrance and passages that branch through the rock, creating a network of connected chambers.

Oscar Decombaz visited the entrance lake by boat in 1899. In 1947 Jean Deudon climbed above the lake into a fossil gallery that André Bourgin's team explored for nearly 2,000 metres. Pierre Chevalier climbed a 12-metre waterfall in 1952, and in November 1976 three speleologists, Michel Schmidt, Roland Chenevier and Daniel Trouilleux, were swept away by a flood.

Speleologists have long regarded Gournier as the finest underground river in the Alps, a reputation built during the explorations from 1947 onward. The entrance lake was first visited by boat in 1899 by Oscar Decombaz. The cave is private property, and the 1976 flood that killed three speleologists from the Rhône region remains part of its story.

Visitors should expect cold temperatures around 6 degrees Celsius and bring suitable clothing and gear accordingly. Waterproof clothing, protective equipment, and reliable lighting are needed to safely navigate through the damp passages.

The entrance porch holds a 40 m lake, and above it a 2 km fossil gallery up to 20 m wide with stalagmite floors; four openings in its floor lead down to the underground river. The cave is private property near Choranche.