The Roman walls enclosing the Cité Plantagenêt are among the finest surviving examples of late Roman military architecture in Europe. Built between the 3rd and 4th centuries, they stretch for some 1,300 metres around the hilltop old city, reaching up to 10 metres in height in places and incorporating several semicircular towers.
What makes them particularly striking is the decorative polychrome inlay: bands of orange and red brick alternate with courses of stone in geometric patterns, giving the wall a distinctly ornamental quality that goes well beyond simple fortification. You can walk the full circuit of the exterior, and in several sections the medieval city grew so organically around the Roman masonry that the two are now inseparable. One of the towers, the Tour Madeleine, retains its Roman stonework almost intact.