Here is a close-up of the campanile (above-left). The tower was built in 1173 to serve as a light house and its present appearance dates back to the early 16th century. However, the original tower collapsed in 1902 - but was rebuilt to its original form ten years later. There are five bells in the tower - each bell with a different purpose. For example, one of the bells tolled the start and the end of the working day, whereas another warned of an execution. Similarly, one of the bells was dedicated to summon senators to the Doge's palace. I took the picture of one of the bells (above-right) - hoping that this is the execution bell.
In case you are wondering about the views from the Campanile, here are three images (below) taken from the top of the tower (also, the picture of the tiny island of San Giorgio Maggiore on the Peter Greenaway post was taken from the top):
I also had a chance to give a lecture about Galileo to a Venetian cat. The telescope bit went quite well (below-left) but I began to loose my audience (below-right) when I started talking about Galileo's theory of tides.