The historic center of Siena is a UNESCO World Heritage Site. The city's most famous attractions include the Siena Cathedral ("Duomo"), one of the great examples of Italian Romanesque-Gothic architecture, featuring art by Donatello, Ghiberti and others; Museo dell'Opera del Duomo, with its collection of works by Sienese master artists; and the Church of San Domenico and Pinacoteca Nazionale, which both house treasured 13th and 14th century art.
The Palazzo Pubblico, with its impressive façade, holds court over the shell-shaped Piazza del Campo, the town square, alongside the famous Torre del Mangia, (meaning "Tower of the Eater"). Both are considered architectural treasures. The Piazza is also famous for hosting the Palio, a traditional medieval horse race held twice yearly on July 2 and August 16, and where rivalries between the city's 17 wards run rampant.