Amelia is especially known for its walls, parts of which may date to Amelia's earliest days. Large segments of the wall are built in polygonal masonry of carefully jointed blocks of limestone. A 30-meter segment of this wall collapsed in 2006 and is under repair. The walls were further fortified and enlarged during Roman times and at various times during the Middle Ages. The walls run about 720 meters and are about 3.5 meters thick, and have four main gates: the imposing Porta Romana to the south, the main access to the town; Posterola to the north; Porta Leone to the east; and Porta della Valle to the west.