1-646-395 - Ann Ronan Picture Library/Heritage-Images

Air filters, Maginot Line, France, 1939. Conceived by Andre Maginot (1877-1932) as an impegnable wall on France's eastern frontier, the Maginot Line was a vast linked set of fortifications, tank traps and other obstacles, mostly built between 1930 and 1935. In the event of World War II, the line proved completely ineffective, as the invading Germans simply bypassed the fortifications to the north, passing through the supposedly impenetrable Ardennes forest and neutral Belgium.