ティエールの城壁
The demolition of the Thiers wall during the 1920s allowed for the creation of this ring of boulevards surrounding the city, using the land just inside the wall itself. Later, the Boulevard Périphérique, a short distance 'outboard' of the Boulevards of the Marshals, was built on the site of the Thiers wall itself, though it is more like a motorway than a wide boulevard.