The parish church of Santa Maria extra Muros sits just outside the line of the old walls — the Latin name simply means "Saint Mary outside the walls." The core of the building is eleventh-century, with substantial fifteenth-century alterations that gave it the current three-aisled plan.
The four-storey campanile is the most distinctive feature, with progressively larger arched openings on each level. Inside, look for a number of medieval and early-Renaissance stone fragments built into the walls and pillars.