Via XX Settembre and via Borgo Saffi - The houses located along the perimeter of the quadrilateral, built between 1698 and 1708, and those included in the Borgo Saffi, built between 1790 and 1813, were born to accommodate the families of the salt workers who worked for the Papal State. The salt workers themselves contributed to the construction of the city and thus acquired the right, which can be passed on from father to son, to enjoy free accommodation. This right was recognized until 1953, when the leadership of the State Monopoly eliminated all privileges. Along the quadrilateral there were 48 houses; each house consisted of eight rooms, almost always divided by four families. The appearance of the city from the outside resembled that of a fortress. However, at the end of the construction of the houses of the salt workers along the quadrilateral, not all the families had a house. In 1790 the construction of the village of the salt workers, or Borgo Saffi, began. The whole complex consisted of eight houses, four on each side of the road, for a total of 96 rooms, plus services and courtyards, divided into 48 apartments.