The Rialto Bridge is the oldest of the four bridges spanning the Grand Canal. Initially, the crossing was secured by boat and only in the twelfth century was a wooden bridge built, with a mobile central structure, called 'of money' because it linked with the mint. The growing importance of the Rialto market has resulted in its name change to that of the bridge that collapsed in 1444 under the weight of the large crowd gathered to watch the passing of the procession of the Marquis of Ferrara bride. The current single-arched stone bridge was built by Antonio da Ponte in 1591 with a very similar to the previous wooden bridge structure: two inclined ramps, with shops on both sides. The whole bridge is covered by a portico. Considered overly risky engineering according to many architects who forecast it should have collapsed.