In 1333 Azzone Visconti, at the conclusion of the period of wars that had led the lords of Milan to finally conquer Monza as well, had a wall with a perimeter of about 3 kilometers erected, intended to protect the central core of the village. The walls were welded to the south around the great Castello Visconteo, of which only the Torretta visible from Via Visconti remains today; on the eastern side, for greater protection, an artificial branch of the Lambro, the Lambretto, was dug.
The moat begins at the very spot where the stone Ponte Nuovo was built, to this day the oldest existing walkable bridge in the city. From the bridge it is possible to see the base wall of the medieval walls, demolished in the 19th century.
