St. Mark's Square (Piazza San Marco) is Venice on parade, where everyone comes to see and be seen. It is Venice's only square with the title of "piazza" - the rest are called "campo." Life has revolved around this piazza since the days of the Republic, when it was a market as well as the center of civic and religious life. Considered one of the finest squares in the world and certainly Venice's prime attraction, it is surrounded on three sides by the stately arcades of public buildings and on the fourth, by Basilica di San Marco's riot of domes and arches and the soaring campanile. No obstruction mars its vast stone-paved expanse, where the only traffic is Venetians, tourists, and the ever-present pigeons