It is called the Leaning Tower or the Tower of Pisa but actually it was never used for defending the city; it is part of the religious complex in the Duomo Square and acts as its bell tower. It played an active role in both human and divine timekeeping with its seven bells – one for each musical note – the largest of which, cast in 1655, weighs a full three and a half tonnes! It is known throughout the world for the beauty of its architecture, for its extraordinary tilt, which makes it an authentic miracle of statics, and for the fact that it stands in the universally renowned Piazza dei Miracoli, of which it is certainly the prize jewel. And this is why it is one of the 7 Wonders of the World.