Close to the waterfront, the 'Old Fort' was constructed to a design by Antonio de Sangallo the Elder in the 16th century, but incorporates an 11th-century watchtower from a previous fortress on the site. An edgy arts and culture venue today, the fort rocks with 'summer vibe' dance parties, live jazz, contemporary-art exhibitions and all sorts of fun happenings.
Check its Facebook page for what's on.