The state art gallery, in the 15th-century Palazzo Buonsignori. It holds the most complete survey anywhere of Sienese painting: Duccio, Simone Martini, the Lorenzetti brothers, Sassetta, Giovanni di Paolo, Domenico Beccafumi. The gold-ground panels of the early rooms — Madonnas with elongated necks, severe Christs, infinite spatial recession — are an alternative history of European painting to the Florentine Renaissance.
It is often quiet, almost meditatively so. Allow at least an hour and a half.