Most cruise ship passengers make a beeline to Rome from Civitavecchia, but this stretch of Tyrrhenian coastline is home to delightful, lesser known sights. Discover one of the most fascinating with this shore excursion to the 14th-century Castle of Santa Severa set directly on the water’s edge. Take in the castle complex at your own pace, admiring views from the ramparts and visiting the archaeological and nautical museums housed inside.