See the Duomo Nuovo (New Cathedral) and check out the Piccolomini Library, dedicated to Pope Pius II. Oh, and don't forget to look down. The floor is an art piece in itself, with 56 scenes engraved in marble, which were carved between 1369 and 1547 by 40 different artists. You'll step lightly, but the complexity is staggering! Please note that the floor is visible in its entirety from 27/06 to 31/07; 18/08 to 18/10 at 10:00 - 19:00, while on holidays the opening time is 9:30 - 18:00. During the rest of the year, some parts are covered. Enter one of Italy's most important Roman-Gothic style buildings - the magical Cathedral of Siena - and marvel at the frescoes by Donatello, Michelangelo, ...