Pont des Invalides

The Pont des Invalides holds the distinction of being the lowest bridge in all of Paris. Because of its remarkably low elevation above the Seine, engineers installed a specialized sensor on the central arch to constantly monitor the clearance for passing boats, preventing any collisions with the structure. This need for precision is a direct result of its history of engineering challenges, as the current masonry bridge was built in a hurry for the 1855 International Exposition after two previous suspension bridges on the site failed and had to be demolished.