The Piazza del Comune is the heart of the visit: the Cathedral, the octagonal Baptistery, the Torrazzo bell tower, and the Loggia dei Militi all stand here, forming one of the finest medieval civic spaces in Italy. The Museo del Violino nearby is essential — a superb museum of luthiery with original Stradivari instruments. The Teatro Ponchielli is an elegant 19th-century opera house that has a regular season. For those interested in Romanesque architecture, San Michele and San Sigismondo are worth the short excursion from the centre.