The walls of Jesi are the old defense wall of Jesi. It is one of the most complete and best preserved in the Renaissance period and one of the greatest examples of the region. It encircles the medieval nucleus of the city, with its compact trapezoidal shape. They were erected from the 13th to 14th centuries on the route of the oldest Roman walls of the castrum, extending it, representing the symbol of communal freedom. The walls were part of an exemplary and complete defensive system that included constructive elements and natural integration: the Urban Fortress, located on the highest area of the city, the last bastion to defend against external attacks. the tower of the Guard, erected around 1350 on the top of a southern hill dominating the Vallesina from which you had a visual capability from the Apennines to the sea; the valley, a canal also used for irrigation of the entire Vallesina, and which constituted a natural defensive embankment around the southern section of the walls, which can only be crossed with lifting bridges at the entrance doors. Finally steep slopes on the north and east sides. The enclosure develops for a length of about one and a half miles, and its conformation varies in relation to the soil morphology that has differentiated levels of level, from the plain to the hill. It was during this period that the Ghibelline burials that characterized the mural profile were demolished and politically identified the city. Indeed, in the 15th century, the bait had lost their function with the advent of firearms. The walls appear as high walled walls, reinforced by turrets and open by seven doors. Today, only four of them are left open, at the entrance of the four cardinal points according to the old two-way route: Cardo and Decumano. On the north side is Bersaglieri door, the latter being open; west leads to Garibaldi, to the east the arch of the Magistrate, part of the old fortress, and to the south leads Valle, on the base walls. The walls of the southern part, enclosed between the Round Tower and the Tunnel of Mezzogiorno (1454), were lined with a moat, now undercut, and are "low", featuring simple vertical curtains with beak and cattails. They are made taller and more impressive on the eastern slope, sloping on the slopes, which have reinforced curtain walls for greater protection against artillery. The whole area is surrounded by defense towers and angular towers. The major is the polygonal tower of Mezzogiorno, so-called by its position, built by Baccio Pontelli in 1454; the Round Tower, located at the east corner of the "Valle" Wall; the tower of Montirozzo, which became the symbol of Jesi, the only rest of the 14th century walls still visible, where in the seventeenth century was raised the characteristic two-story torricino and loggias. Other varied polygonal towers intersect along the perimeter, two are lost, the tower of the ancient fortress of San Floriano, set in defense of Garibaldi gate, demolished in the 1920s for the extension of the road; and the tower of Rocca or Cassero, overlooking the square of the Republic, next to the arch of the Magistrate, and demolished in 1890, was the last rest of the Pontelliana Fortress, which stood on the highest part, the northwest where the extension was opened of the "new" city, the so-called "Terravecchia Addition". It was built on Baccio Pontelli's design, which had been demolished in 1487 since 1587. Previously there was another fortress, built in 1282 and destroyed, perhaps only partially in 1423 and then reconstructed from 1433 by Francesco Sforza . The two rocks (that of the 13th-century and the Pontelite) are still under the adjoining municipal building. Still present, it is pusking through today's "Battle Palace".