The great block of the castle around its yard is then enclosed in its turn by a larger walled courtyard (lower courtyard) and is situated on a natural terrace of the Ticino. It has the classic square layout of the Visconti lowland castles. Surrounded by a moat it has no towers at each of the corners which may be due to the fact that it was primarily intended as a residence. Today it has a horseshoe shape due to the loss of the south wing, the same fate that befell the castle in Pavia. Apart from the magnificent double lancet window it also has remains of a drawbridge at the entrance. It also has swallow-tail battlements, with very narrow embrasures. Construction period: 14th–15th century. The Town Hall is now located inside the castle together with the Pro loco tourist office, some voluntary associations, a theatre and the town library.