One of the architectural icons of Venice, Ponte di Riato, the Rialto Bridge, is one of four bridges spanning the Grand Canal. This is the third bridge to span the canal at this point. As early as 1181, a pontoon bridge was located here. Because of the growth in commerce on the eastern approach to the bridge, the pontoon bridge was replaced in 1255 by a wooden bridge with a movable center section that allowed tall ships to transit. The wooden bridge had two inclines that featured stalls, the rents from which provided income for the maintenance of the bridge. Following two collapses, a stone bridge was proposed in 1503 and finally completed as you see it here in 1591. Like its wooden predecessor, the Rialto Bridge is lined with stalls for rent by merchants.