The Piazza originated in the 9th century as a small area in front of the original St Mark's Basilica. It was enlarged to its present size and shape in 1177, when the Rio Batario, which had bounded it to the west, and a dock, which had isolated the Doge's Palace from the square, were filled in. The rearrangement was for the meeting of Pope Alexander III and the Emperor Frederick Barbarossa.
St Mark's Clocktower is a clock tower situated on St Mark's Square in Venice, adjoining the Procuratie Vecchie. It houses the most important clock in the city, St Mark's Clock (alternatively known as the Torre dell'Orologio or the Moors' Clocktower).
It was constructed as a display of Venice's wealth, and as an aid to sailors on the Grand Canal about to depart on a voyage.
The building was designed by Mauro Codussi and constructed between 1496 and 1499. It has five bays, of which the central bay is the widest. This bay incorporates a two-storey gateway, with the large clock face above, topped by a single storey tower with a depiction of a Lion of St Mark against the night sky, while two blackened bronze figures intended as giants but known as the "Moors" stand on top and ring a bell on the hour.
The Procuratie in are three connected buildings on St Mark's SquareVenice. They are also connected to St Mark's Clocktower. 
St Mark's Basilica, the cathedral of Venice, is the most famous of the city's churches and one of the best known examples of Byzantine architecture.
One of the tourist favorites in the plaza is feeding the pigeons. So they swarm there to get the food the vendors sell. Many folks allow the birds to land on them and eat out of their hands. I was a little creeped out by the idea of it and basically would walk through them waving my hands to try to keep them from landing on me. I made it without a landing the first trip through them, but wasn't so lucky the second time. I'm sure there is a tourist out there somewhere with a picture of me jumping and screaming like a girl as I tried to get the pigeon off me.
And finally, my lame attempts at trying to get the wonderful view along the grand canal. It just can't be fully captured.
