Crésuz-Gruyères par les gorges de la jogne 

The Jogne Gorge is a deep gash in the Earth sculpted by underground stream systems. The gorge links the Jogne Valley, at 800 m altitude, to the Sarine Valley, about 100 meters below. About 2 km long, the gorge is very narrow, with steep vertical sides, at times towering over 100m high. A variety of rock formations dating to the Jurassic period are particularly visible. Jogne Limestone, rather resistant to erosion, forms the narrowest passage of the gorge, where tunnels and bridges have been built to allow hikers to navigate the gorge on foot. Today, the flow and dynamic of the Jogne River have been altered by the presence of Montsalvens Dam. High water periods are artificial and depend on the workings of hydroelectric installations. A portion of the stocked water in the retention lake is diverted into the conduit turbines of Broc-Fabrique to produce electricity. The water then returns to the river downstream of the gorge.

This dam, located along the Jogne river, is responsible for Montsalvens lake. Built between 1918 and 1921 by engineer Heinrich Eduard Gruner, it was the first arch dam in Europe with both horizontal et vertical curves. 52m high and 110m long, its construction required 26’000 m3 of concrete.