Fort l'Écluse
Fort l’Écluse is a fortress near Bellegarde-sur-Valserine. It guards the Rhône valley between the Vuache hills and the Jura Mountains and is a natural entrance into France from Geneva. The fort was founded by the Duchy of Savoy in the 13th century and, after it was ceded to France along with the Pays de Gex during the reign of Louis XIV, completed by Vauban. It was destroyed by the Austrians in 1815, but was rebuilt by the French and considerably strengthened and heightened. The fort is open to visitors during summer.