France Builds World's Greatest Defense System

Well, history sure did a number on the above statement.  As revealed in this 1931 Modern Mechanics article posted on Modern Mechanix, the Maginot Line was an engineering and technical marvel, with its self-contained living quarters, underground transportation, ammunition storage, and fortified weapons emplacements.  The fatal flaws?  It was stationary, and it stopped at the Belgian border.  In 1940, German Panzer divisions pushed straight through the Ardennes, which was so thick that French and British military commanders considered it impassible for tanks, and simply went around the Maginot Line through Belgium into France.