The atmosphere of the medieval town is felt in the labyrinth of narrow winding streets, closely built houses with secluded court-yards and covered passages.
Outside the nucleus a castle surrounded by a moat and drawbridge was built around 1300. Two castle towers controlled the approach from the north and south.
Although the historic core was not surrounded with town walls, the historic contrade Merceria, Forno grande, Portarol and Duomo, Callenuova, Pian and Sv. Katarina had gates. The castle was surrounded by public buildings: barley storehouse, which was part of the complex of town loggia, archives, chancellor's office, as well as granary. The present-day town square was formed after the castle was destroyed in 1808.
The ground plan of the one-time cistern and castle in today's main square is marked with white stone slates.