Fosse Dionne is a karst spring (a karst is an irregular limestone region with sinkholes, underground streams, and caves, according to Merriam-Webster) that spits an average of 82 gallons (311 liters) of water per second, which is a unusually high flow. rate for this type of spring, but the speed at which it springs from the ground varies from season to season. What you might see from the spring if you visited the Fosse Dionne, which translates to ‘divine pit’, is a circular stone swimming pool built in the 18th century, filled with water in jewel tones: turquoise, amber and cerulean, colored by the minerals in the limestone caves from which the waters emerge. The opening of one of these caves is visible from the edge of the basin.
Because humans have been using Fosse Dionne since before anyone keeps track – for drinking, washing, cooking and bathing – there are stories and legends about spring, some we know and some we don’t. do not know. In the Middle Ages, it was believed that there was a serpent cruising deep within the heart of the Dionne Pit, and some even thought it was the portal to another world. The spring figures prominently in accounts of the miracles performed by the 7th century monk Saint-Jean de Rèome, who arrived in the area in AD 645 to clean the spring, which at the time was a swamp unusable. The monk would have dug a basilisk – half rooster and half lizard -om the source and killed it, allowing people to find the use of the Dionne Pit for drinking, washing, etc.
These days, Fosse Dionne looks very civilized from the outside, in her stone basin surrounded by a to see her, a common laundry room, built in the 18th century to protect washerwomen from the elements while they were doing their laundry in the spring. But under the surface of the water, the source is just as wild as when Saint-Jean de Rèome arrived to tame it.
The great mystery of the source of the Fosse Dionne is the origin of its water. There is certainly a lot of water coming out of it, and like other karst springs, the water emerges from a network of underground limestone caves. However, no diver has ever been able to find its source, and many who have tried have not returned alive.
No one even attempted to probe the depths of the Fosse Dionne until 1974, when two divers set out to navigate the spring’s maze of narrow chambers and tunnels. None of these divers returned to tell what they had seen. In 1996, another diver tried him, but he also lost his life due to the Fosse Dionne. For many years after, divers were prohibited from diving in the spring until 2019, when diver Pierre-Éric Deseigne set out to explore 370 meters of passages. Fortunately, he came back alive but did not find the source of the source – nor find another dimension or a monstrous serpent.
We still have time.