Pienza is probably the most renowned and most important art of the Val d'Orcia. Gran part of the relevant historical and artistic heritage of Pienza is concentrated in the picturesque square dedicated to Pope Pius II, the personality that has given so much to the town, looking to make it his "ideal city" of the Renaissance. It is not far from the highway Cassia and the other two major towns of the valley, San Quirico d'Orcia and Castiglione d'Orcia. The historic center is a UNESCO World Heritage Site in 1996.