The existence of this cave has long been known to the local population. In the middle of the vineyards it could hardly escape the notice of the vine-growers who used to cool their bottles of wine in this cold mysterious water.

However, no one is known to have ventured into its depths, undoubtably due to a lack of means and to superstitious fears inspired by the unknown subterranean world.

In 1943, Jean-Jacques Pittard, accompanied by Jean Della Santa, used an inflatable boat to enter the cave. The two explorers were amazed by the size and beauty of the place, they landed on the beach at the far end, visited the far most cave and returned.

In 1949 the lake was opened to the public as a result of the efforts of two young men of St-Léonard. Since then, a lot of work has been done in order to offer more and more comfort and safety to visitors.

Today the cave is remarkably illuminated and very easy to reach. Several boats are available with guides to point out the sights and answer the various questions of the tourists.