Sant'Eulalia Museum

Tucked into Cagliari's Marina district, this museum holds a remarkable collection of silverware, paintings, religious tapestries, and wooden artifacts that trace the area's deep Catholic heritage — plus an underground archaeological site where you can wander among actual Roman-era ruins. What makes it special is that they rotate contemporary art installations down among the ancient remains, creating an unexpectedly striking contrast between old and new. Admission covers both the treasure collection and the archaeological area, so you get a lot more than you'd expect for the price.