Civitella San Paolo has the characteristic of being surrounded by three concentric series of walls. The oldest and best preserved, can be recognized near the Porta Capena. The second circle of walls dating from the thirteenth century corresponds to the oldest part of the village. These were punctuated by a series of square towers like the one still in via Cavour, that became a private residence, and is largely incorporated in the urban fabric. The third circle is dated around the end of the fifteenth century and is punctuated by towers and ramparts. It is attached directly to the castle and has two entry doors. The walls followed the contours of the ground and had to protect the portion not covered by the castle artillery.