More info: The San Marco basin is an area of the Venetian Lagoon that faces the Riva degli Schiavoni and Doge's Palace of the San Marco sestiere. The Grand Canal and the Giudecca Canal both merge in to St. Marks Basin. In the middle of the view you see the domed church of Santa Maria della Salute a massive 17 century church built to thank God for ending the plague epidemic in the city.
Venice was founded in the 5th century and is spread over 118 small islands. The islands are connected by more than 400 bridges spanning around 160 canals.