Alpine Maginot line The Guardians of the Alpine Maginot line. The story of the less known part of the French Maginot line – a line of underground fortresses in the alps on the border between France and Italy. My video based on much research will take you to back to 1940, 2000 ft above sea level and underground in these fortresses, inside their multilevel bunkers – artillery blocks, armoured entrances, galleries, machine gun and mortar cupolas.