Just a short walk from the old streets of the town, a place has fascinated visitors for centuries: the Fosse Dionne in Tonnerre. With its turquoise water and mysterious origin, it intrigues both locals and travelers passing through.

It is as mysterious as it is beautiful. This powerful turquoise spring, with its impressive flow, has inspired many legends over the centuries and remains an enigma even for modern cave explorers.
Between natural curiosity, historical heritage and local legends, the Fosse Dionne is one of the most iconic sites to discover during a stay in Tonnerre.