The 4km-long walls already existed when the Knights Hospitaller arrived, but they rebuilt them almost in their entirety, always reinforcing them more. The walls were at that time divided into sections called "boulevards", each of which was defended by one nation. The walk runs along the different boulevards, allowing you to see up close the defences reinforced by bastions. Flanked by two turrets, the D'Amboise Gate (1512) is the most impressive.