Lac de Pérolles is a reservoir formed by the Maigrauge Dam on the Sarine river, just south of the old town. The lake and its forested banks form an attractive green corridor that Fribourg residents use for walking, running, and swimming in summer. The path around the lake is roughly 7 kilometres and takes about two hours at a comfortable pace.
The dam itself, built in the early 20th century to power the city's electric tram system, is a neat piece of industrial heritage. The water at the lake's swimming area is clean and cold — this is not a Mediterranean beach, but on a hot summer day the combination of the Fribourg hills and the clear reservoir makes for a pleasant afternoon out of the city centre.