A Cathedral of Calcite
The Grotte des Demoiselles is a vast network hollowed out from the Jurassic limestones of the Massif de Thaurac. The cave's formation began millions of years ago when water eroded the fragile rock, causing overlying limestone to collapse. The main chamber, known as the "Cathédrale Souterraine" or Underground Cathedral, has dimensions comparable to a large church: 52 meters high, 48 meters wide, and 120 meters long.
Inside this chamber, water with dissolved calcium carbonate has dripped for millennia, depositing calcite and forming a vast collection of speleothems. The most famous of these is a massive stalagmite named the "Vierge à l'Enfant" (Virgin and Child). This specific formation is one of many in the cave, with some concretions dated to be as old as 264,000 years. The active concretion process continues today, evidenced by the very white top of the "Virgin and Child" stalagmite. Other formations include immense translucent draperies and large columns that resemble organ pipes.
From Legend to Science
Local stories about fairies or "demoiselles" gave the cave its name long before its scientific exploration. According to one legend, a shepherd who fell into the cave was rescued by dancing maidens. For centuries, the cave was a refuge for various groups, including Camisards during the French Wars of Religion.
The first documented scientific exploration occurred on July 15, 1780, led by Benoît-Joseph Marsollier des Vivetières. The pioneering French speleologist Édouard-Alfred Martel who conducted the first methodical explorations in 1889 and reached the bottom of the cave in 1897, at a depth of 90 meters. To measure the height of the main chamber, Martel even used a hot air balloon. The cave was opened to the public in 1931, featuring a technological innovation for the time: the first underground tourist funicular in Europe. This railway ascends 54 meters through the rock, avoiding a climb of several hundred steps. During the development work in 1929, the skeleton of a cave bear, Ursus spelaeus, was also discovered.