The history of bridges in Venice is closely linked to the city's unique location, built on over 100 small islands in a lagoon on the Adriatic Sea. As Venice is criss-crossed by numerous canals, bridges were of crucial importance to connect the different parts of the city. The first bridges in Venice were built as early as the 12th century. One of the oldest known bridges is the Rialto Bridge. Another famous bridge is the Bridge of Sighs (Ponte dei Sospiri), which was built in the 17th century to connect the Doge's Palace with the prison. Today there are more than 400 bridges in Venice. Bridges in Venice are not only functional structures, but also symbols of the connection between people and the city's neighborhoods. They characterize the romantic and mystical image.