Siena Cathedral (Duomo di Siena): A stunning Gothic cathedral with an impressive marble facade. Inside you will find special mosaic floors, works by Michelangelo and Donatello, and the Piccolomini Library decorated with frescoes. [The Siena Cathedral was built between 1215 and 1263 and is considered one of the most beautiful examples of Gothic architecture in Italy. For history and art lovers, the Siena Duomo is a real feast – works by Lorenzo Ghiberti, Michelangelo, Nicola Pisano and many others adorn it, and the floor of the cathedral is made entirely of a wonderful marble mosaic, depicting biblical and mythological scenes (note that for most months of the year the floor is partially covered, and is fully visible to tourists only for two months of the year). Also hidden inside the Duomo is the wonderful Piccolomini Library. The library was built by the pope’s family, a member of the Piccolomini family of Siena, and is decorated with a magnificent fresco cycle, which has been preserved to this day in bright colors. Behind the Duomo is also the Duomo Museum (opera del duomo) and the baptistery (included in the ticket price, and highly recommended for a visit). Museo dell’Opera: The cathedral’s art museum, where you can see original sculptures by Giovanni Pisano and climb to the unfinished part of the new cathedral for an excellent view. [ Open from 10:00 to 19:00.