2-611-836 - Keystone Archives/Heritage Images

French General touring the Maginot Line, c1935-c1940. France built the system of fortifications known as the Maginot Line in the 1930s to protect its eastern frontier from invasion. In the event of the actual invasion in 1940, the Germans simply bypassed the supposedly impregnable line. Instead they entered France through the Ardennes, a strategy disregarded by the French due to their belief that the terrain would be impassable for tanks.