A museum dedicated entirely to Lac Léman — its geology, fish (including the giant catfish that occasionally turn up in nets), traditional sailing boats, the steamships of the Belle Époque, and a working aquarium of the lake's freshwater species. The building was originally a 19th-century mansion built on the waterfront for a wealthy local merchant; it became a museum in 1954.
The aquariums on the ground floor are popular with children; the upper floors are more historical. Outside, the lakefront garden holds a restored late-19th-century barque — the broad, low cargo boats that once moved limestone and wine up and down the lake. Closed Mondays. The lakefront promenade runs directly past the entrance.