The Rialto Bridge, Venice.

 This is probably Venice's most famous bridge, and is to all intents and 
purposes _the_ symbol of the city. It was built in the 16th century to replace
an earlier wooden bridge, and was designed so that a fully armed war-galley
could pass underneath. It was for many years the only bridge over the Grand
Canal; even now there are only three bridges connecting the two halves of
Venice.

 (Chris Owen - tr95006@sable.ox.ac.uk)