The Barrage Vauban: a bridge, weir and defensive work built in the 17th century. Its main defensive function was to raise the level
of the River Ill in the event of an attack, thus flooding the lands south of Strasbourg, making them impassable to the enemy.
The measure was last deployed in 1870, when Strasbourg was beseiged by Prussian forces during the Franco-Prussian War.
The roof was rebuilt in the 1960s to porovide a panoramic terrace.