The Fosse Dionne is a karst spring, in Tonnerre in the Yonne department of France. It is fed by the rainwater on the surrounding hills as well by at least one subterranean river. The Fosse Dionne is remarkable because of its average daily outflow of 311 litres per second.
It is likely that the spring was the reason for the siting of the village. An elaborate lavoir was built around the spring in the 18th century.
Wikipedia https://en.wikipedia.org/wiki/Fosse_Dionne
Address 29 Rue de la Fosse Dionne, Tonnerre 89700, France
Coordinates 47°51'23.65" N 3°58'14.142" E
