Kaštel
Whether from the cathedral or elsewhere along Kandlerova Ulica, a walk up the hill will lead you within minutes to the 17th-century Venetian fortress, the Kaštel, that towers over Pula's city center and houses the Historical and Maritime Museum of Istria. Built on the site of a pre-Roman fort, the preserved star-shaped fortress dates back to 1630 and has four bastions. Despite its 100,000 items of cultural, historical, political, military, and ethnographic character displayed across 18 collections, the museum is somewhat lackluster. However, it does carry the value-added benefit of allowing you to wander around its ramparts.
Simply walking around its perimeter offers fine views of the city's extensive shipyard below and, if you look to the north, the steeple of Vodnjan's church 12 km (7½ miles) away.
