The Arzviller Inclined Plane, the Rock of Dabo and Chagall's Window

Required Activities

• Watch the 900-tonne tank ride the ramp of the Saint-Louis–Arzviller inclined plane, then go into the machine room and find the two 450-tonne concrete counterweights and the fourteen 27 mm steel cables that hold each one to the tank — the reason two 90 kW motors can move the whole thing, since a boat entering the tank displaces its own weight of water and the load never changes

• Climb the stair cut up the side of the Rocher de Dabo — a sandstone block 30 m high, 80 m long and 26 m wide, topping out at 664 m — to the platform where the chapel of Saint-Léon stands, then go up inside its bell tower, rebuilt in 1889 and built to serve as the belvedere, for the turn round the whole northern Vosges

• In the Chapelle des Cordeliers at Sarrebourg, stand under Chagall's wall of glass on the theme of peace — 12 m high by 7.50 m wide and 900 kg, delivered in 1976 — and find the point where it was fitted to close the gaping hole left at the west end when the old barracks round the chapel were pulled down

• Take the hour-long boat trip up to lock 17 and back over the inclined plane, or the little train down into the old valley, and count the abandoned chambers of the ladder of 17 locks that boats used to crawl up all day