Ouvrage Cave-à-Canon is a lesser work (petit ouvrage) of the Maginot Line's Alpine extension, the Alpine Line. Started in 1937, the ouvrage consists of one infantry block about one kilometer east of Bourg St. Maurice, on the south bank of the Isère. A short gallery with cross galleries extends into the rock, with an emergency exit and ventilation shaft halfway back.The ouvrage was incomplete in 1940, under the command of Lieutenant Courteaud.