Travelling along the small roads following the Franco-Belgian border it is possible to see a wide variety of small bunker designs. A few still have the earth camouflage cover making them appear rather like tumuli but most are clear and vary from small machine gun only positions to larger designs intended to house an anti-tank gun. While the materials used are usually reinforced concrete, occasionally you will see brick covered designs such as the British built bunker near Deulemont which still has a hefty concrete roof. By June 1940 these provided little impediment to the invading mobile German army although many saw futile yet brave defences by allied troops. Despite the lesson of the failure of such defences in the face of a strong and mobile army, the Germans spent the next four years building the defences of the 'Atlantic Wall' stretching from Norway to Spain all down the Atlantic coast ,and the 'Siegfried Line' defending the German border. The Atlantic Wall was largely defeated and bypassed in one day on 6th June 1944 and while the Siegfried Line took a little longer, and many casualties, it did not stop the inevitable overpowering of its defences by the vast weight of the Allied armies. It was perhaps fortunate for the Allies that the Germans had wasted so many resources on these pointless and outdated defences as it tied down huge quantities of men and material which might have been more useful in a more mobile force.