Built in the second half of the 3rd century, the Gallo-Roman fortifications protected the vicus from Germanic invasions. These oval-shaped ramparts, measuring 850 metres in circumference, wind their way around Saint-Donat hill, also known as “Knippchen” hill. A dozen towers are built into the walls, at intervals of approximately 65 metres. Measuring 8 to 9 metres with a thickness of up to 3.8 metres, these walls allowed the vicus’s inhabitants living along the Semois below to take refuge inside the city walls, with their livestock, crops and provisions. The path leading to the Grand-Place skirts the remains of the fortifications which, in some places, have been used as the back wall or foundations for the houses located on the right.