While it is called the Leaning Tower or Tower of Pisa, it was never used to defend the city; instead, it serves as a bell tower for the religious complex in Duomo Square.
With its seven bells - one for each musical note - the largest of which weighs three and a half tons - it played an important role both in human and divine timekeeping. The building is known throughout the world for its beauty, its extraordinary tilt, which makes it an authentic miracle of statics, and its location in the world-famous Piazza dei Miracoli, of which it is undoubtedly the crown jewel. Because of this, it's considered one of the 7 Wonders of the World.