old historical hump line in the forest . cusp-d or tooth-d concrete anti-tank barriers . defense fence against enemy

antitank barriers autumn background barrier beautiful border security wall bunker cold concrete cone cuspshaped day defense line system dragons teeth environment forest germany green historic site historical hump landmark landscape leaf leaves military monument natural nature obstacles old outdoor park scenic season siegfried sky spring tank tree trees trunk water wood woods cusp-shaped tooth-shaped anti-tank fence against enemy vehicles location north german city aachen wwii