The cathedral museum, in the unfinished right aisle of the never-completed Duomo Nuovo. The single most important room contains Duccio di Buoninsegna's Maestà (1311), painted as the high altarpiece of the Duomo: a vast double-sided panel of the Virgin in majesty on one side and the Passion narratives on the other.
Other rooms hold original sculptures by Giovanni Pisano (the apostles and prophets of the Duomo façade, now replaced by copies) and Donatello. The narrow stone staircase up to the Panorama dal Facciatone — the top of the unfinished new façade — gives one of the best views over the city.