The communal palace in the Piazza del Campo, is famous for its bell tower (Campanile), called Torre del Mangia, erected between 1325 and 1344, with its upper part designed by the painter Lippo Memmi. The tower was designed to surpass the height of the Palazzo Vecchio tower in Florence, their neighbor and rival. At the time, it was the tallest building in Italy. In the mid-14th century, it was equipped with a mechanical clock. Almost all the large rooms inside the palace contain frescos, the most famous of which being by Simone Martini and Ambrogio Lorenzetti. At that time, these frescos were unusual, because they were commissioned by lay governers rather than the church or a religious fraternity.