The old part of the town, the Kastro, is Venetian in origin and dates back to the 13th century. It is a walled city in the shape of a pentagon. Only one of the twelve towers survives, the Crispi, or Glezos tower as it is known today. Enter the Kastro and you enter into a different world. The Kastro is a perfectly preserved medieval town. It has cool and narrow little streets and the old houses still display their family crests. Near the tower is the Venetian museum, the family home of the Della Rocca- Barozzi family which is open to the public.