Made by man in the 1960s to feed a power plant, the ribbon of turquoise water from the Vouglans lake, winds 35 kilometres through the Ain valley from Pont-de-Poitte to the hamlet of Vouglans, in Lect. Its semi-circular dam which is 103 metres tall holds back 600 million cubic metres of water. Every year, it provides electricity to 130,000 inhabitants and, as such, is the second largest hydro-electric plant in France.