Ancient city walls. In via Cecili, the second section of the National Internal Cross-Road mentioned below. This is an interesting insight into the chronology of the ancient city walls. The layer of large polygonal limestone blocks is pre-Roman, fourth-century B:C. The layer in squared limestone blocks and the remains of a watch-tower date back to the foundation of a Roman colony in 241 B.C. The layer in small, soft limestone blocks dates back, instead, to the restoration carried out in the second half of the first century B.C., ie. after the 63 earthquake and the destruction caused by Sulla.