Piazza del Campo is the main square of the city of Siena. Unique for its particular shell shape, it is famous worldwide for being the place of the Palio of Siena. Its history is linked to that of the Town Hall that overlooks: until 1270, the space was used for fairs and markets; fell the government of aristocrats, they began to think of a neutral venue to accommodate the Town Hall, to house the residence of the Podestà, and was chose a hub from which branches off the three main streets. The shape of the Square is a clamshell, inclined to the south, with nine segments defined by white bands on the brick floor. Enclosed by the almost continuous curtain of buildings (including the Mangia Tower, the Chapel Square, the Gaia Fountain and a number of nobles palaces), they branch off eleven gates masked by the use of the time and the arrangement on several levels of buildings. The Town Hall closes the space spectacularly downstream, and towards which all visual, emphasizing the symbolic value. The Square is also famous because it receives, twice a year, the Palio of Siena: a horse race unique in the world, which sees confront the seventeen historical districts that make up the Tuscan city. The race consists of three laps of the Square (sprinkled for the occasion by a layer of dust tuff) a frenzied pace to win the trophy.