partial view of the Rialto Bridge left, center; taken on the Grand Canal in Venice. The Rialto Bridge is one of the four bridges spanning the Grand Canal in Venice, Italy. It is the oldest bridge across the canal, and was the dividing line for the districts of San Marco and San Polo. The present stone bridge, a single span designed by Antonio da Ponte, was finally completed in 1591. It is similar to the wooden bridge it succeeded. Two inclined ramps lead up to a central portico. On either side of the portico, the covered ramps carry rows of shops. The engineering of the bridge was considered so audacious that architect Vincenzo Scamozzi predicted future ruin. The bridge has defied its critics to become one of the architectural icons of Venice.