The Rialto Bridge, connecting the districts of San Marco and San Polo, is the oldest of the four bridges spanning the Great Canal in Venice. Since its first construction as a pontoon bridge in the 12th century, it has been rebuilt several times and once it was the only bridge across the Grand Canal, marking the spot of the island's first settlement, called Rivus Altus, means high bank.

The pontoon bridge, the first of its kind for the pedestrians for crossing of the Grand Canal, was built in 1181 by Nicolo Barattieri and was known as Ponte della Moneta, probably due to the mint that stood near its eastern entrance. However, the pontoon bridge was replaced in 1255 by a wooden bridge, due to the development and importance of the Rialto market on the eastern bank and the consequent increased traffic on the floating bridge.

As it made connection with the Rialto market, the name of the bridge was also changed to Rialto Bridge. It was equipped with two inclined ramps meeting at a movable central section which could be raised to allow the passage of tall ships along the canal. Along the sides of the bridge, two rows of shops were built during the first half of the 15th century and the rent collected from the shop owners brought an additional income to the State Treasury, which helped to maintain the bridge.

But, the maintenance of the timber bridge was a vital problem and a regular headache for the authority. It was partially burnt in 1310, in the revolt led by Bajamonte Tiepoloin. It collapsed in 1444, under the weight of a huge crowd watching a boat parade in the canal and again collapsed in 1524. However, the idea of rebuilding the bridge in stone was first proposed as early as in 1503.Though several proposals were considered, no concrete measure was taken during the following decades. Finally, the authorities requested proposals for the renewal of the Rialto Bridge in 1551 and plans were submitted by famous architects, including Michelangelo. Since all the proposals involved a Classical approach with several arches and ornamentations, they were judged inappropriate.

The present stone bridge, a single span with 24 feet (7.5 m) long arch, was designed by Anotonio da Ponte and the construction was completed in 1591. It looks almost similar to the old wooden bridge and was designed to allow passage of ships. The massive stone structure is based on about 12,000 wooden pilings, which still support the bridge, even after four centuries. Since the bridge consists primarily of steps, it is poses a problem for the physically challenged persons or tourists with strollers to negotiate it. The bridge consists of three walkways, two along the outer balustrades and a wider central walkway. Two ascending covered ramps lead up to the central portico and both sides of portico have rows of shops that sell jewelry, linens, Murano glass, and other interesting items for the tourists.

The Rialto Bridge serves as a busy crossing point midway along the Grand Canal. With Basilica San Marco, Piazza San Marco and Palazzo Ducale, it is one of the most favourite spots of the tourists. The church of San Bartolomeo is also close to the San Marco end of the bridge. On the other side of the Bridge lies the busy food market of Venice, where Venetians and chefs shop for fresh produce and seafood.

The engineering details of the bridge was considered so gutsy and risky, that architect Vincenzo Scamozzi marked it as vulnerable and predicted its imminent collapse in near future. However, the bridge has defied its critics to become one of the most famous architectural icons of Venice and is one of the top tourism attractions in Venice.