The castle dates back to the 13th century, but it includes impressive Renaissance additions which make it an imposing sight. It's also worth paying a few euros to have a look inside, where you'll find the Barons Hall, a chapel, a disconcertingly glass-floored room that you can walk on to view original foundations below, and an exhibition of art and artefacts. It also has excellent top-floor views over the bay.
Piazza Municipio;
tel: 081 795 2003