The "Fosse Dionne" is located in the small and lovely city of Tonnerre. One of the most beautiful springs of France deeply rooted in the history of Burgundy and with an amazing architecture. Right now the access is restricted. The colors are different from what the divers can usually find in the other springs of the area, in combination with gorgeous formations. Sidemount is mandatory and the exit will be in low visibility due to percolation.
Divers: Pierre-Eric Deseigne and Hervé Cordier
