How did Germany avoid the strongest fortifications of the Maginot Line?

The German military bypassed the strongest fortifications of the Maginot Line by exploiting the fact that the line did not extend along the French-Belgian frontier. While the French had constructed an elaborate, heavily fortified barrier from the Swiss border to the vicinity of Montméddy, they relied on weaker, outdated defenses north of that point, assuming that any future conflict would be fought in Belgium.123

In May 1940, the German army executed a strategy—based on a plan devised by Erich von Manstein—that involved a concentrated armored thrust through the dense Ardennes Forest, a region the French incorrectly deemed impassable for tanks. By launching this surprise attack through the Ardennes and invading the Low Countries, German forces successfully outflanked the Maginot Line, crossed the Meuse River at Sedan, and moved into the rear of the French defenses, rendering the fortifications useless.4351