The city was equipped with a wall in polygonal, about 3 km long . Dating back to the fourth century B.C. this wall was equipped with a four-door type sceo, placed at the points of the compass: north port "Follonica" the door to the East "Massa" or "Corfinio", south port "South", in the West door "Maxima". In addition to the colony had cyclopean walls on the south-est flank of the Pettorino precisely, a type of walls in opus almost reticolatum traced back to the time of Silla (I century B.C.).