The Basilica di San Marco sits on a large plaza in the the center of Venice.
Venice was the trading gateway between Europe and the east during the time of Marco Polo. The city prospered and this church is an overwhelming symbol of that prosperity. It's nickname is the Church of Gold.
The winged lion is one of the many statues which adorn the church. It was the symbol of the Republic of Venice which held governing power from the 7th to the 18th centuries.