This is one of the finest examples of the Jura's cluses. The transversal valley in the Montagne du Larmont is just wide enough to accommodate the road and the railroad to Neuchâtel and Berne, which was of great importance. Two forts stand atop the slopes: to the north, the fort of lower Larmont, and to the south the Château de Joux. The best view of the Cluse de Joux is to be had from the monument to the victims of the First World War of Le Frambourg.