Fort l'Écluse

The fort, which was established by a Duke of Savoy, was completed by Sébastien Le Prestre de Vauban during the reign of King Louis XIV.

In his Commentaries on the Gallic War, Julius Caesar describes the defile as "narrow and difficult ... by which carts could be scarcely drawn one at a time, and moreover a very high mountain overhung it, so that very few could easily defend it.

In the end, the Helvetii secured safe passage through the defile via an exchange of hostages with the Sequani, who inhabited the area.

The fort played a part in preventing French Protestants from leaving France following the revocation of the Edict of Nantes in 1685.

A single company of the 179th Alpine Fortress Battalion, augmented with an artillery battery and personnel from a pioneers regiment under Lieutenant Mestrallet held the fort with 250 men against Panzergruppe von Kleist, composed of the 3rd and 4th Panzer Divisions and the 13th Motorized Infantry Division.

After the 25 June armistice, the fort's garrison stood its ground until directly ordered by the French command to stand down and to surrender.

[12] The Fort l'Écluse was purchased by a syndicate of nineteen communities of the Pays de Gex and is operated as a museum.