Among these early settlements, Rivo Alto, its name corrupted over time to Rialto, was the
most central and became the heart of Venice, linking together 118 separate islands with bridges
and canals and subordinating all other settlements to the rule of its elected doge (duke). They
were small islands hardly higher than the level of the water, divided by innumerable small winding
canals, continually swept by the ebb and flow of the tides. The lagoon has always been crucial to
the survival of Venice. Its mudbanks, shallows, and channels are a source of income from
marine and bird life and from salt pans. It has served as protection (the Venetians defeated the
Genoese in 1380 through their superior knowledge of the navigable channels) and as a natural
sewerage system, with the tides flushing out the city’s canals twice a day. More than 200 original
canals have been linked together to form a dense urban network on either side of the curving
Grand Canal, which describes a great backward S more than 3-kilometer long, from the present-