This pontoon bridge was built in 1976 to replace a historical bridge built in the 14th century by the Duke Vespasiano Gonzaga. The old bridge was demolished because was considered hazardous by the Sabbioneta municipality (the bridge was on the edge between Commessaggio and Sabbioneta municipality). nowadays,only the original bricks piers have survived. The historical bridge was filmed in the opening scene of the 1977 film Salo, or the 120 Days of Sodom by the Italian director Pier Paolo Pasolini.
Opposite to the bridge stands the Torrazzo di Vespasiano (the Vespasiano Tower), and which was built in 16th century as duty cease before the duchy entrance.
Source: atlasobscura.com