This square is where it all happens, and is best seen on a Wednesday, when it is taken over by a colourful market. It is bounded by the ogive arcades of a 13C aqueduct, and its south corner is occupied by the former Convento di Santa Chiara, which houses the Diocesan Museum and the Pinacoteca (contemporary and modern art). At the corner of the Vicolo del Vecchio, the Fountain of the Old Man (Fontana del Vecchio) is named after the man's head at the top.