Stand­ing in a large green expanse, Piaz­za del Duo­mo hous­es a group of mon­u­ments known the world over. These four mas­ter­pieces of medieval archi­tec­ture — the cathe­dral, the bap­tistry, the cam­panile (the ‘Lean­ing Tow­er‘) and the ceme­tery — had a great influ­ence on mon­u­men­tal art in Italy from the 11th to the 14th cen­tu­ry.