Fosse Dionne

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.

Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).