#5: The Maginot Line (1929)
France wanted an ironclad guarantee that the horrors of WWI would never happen again. Their solution was the Maginot Line, a massive system of concrete fortifications built along the eastern border starting in the late 1920s. It was an expensive defense marvel, designed to stop a German invasion cold. It only had one issue: the line’s strongest defenses didn’t cover the border with Belgium. In 1940, German forces went around it. They advanced through the Ardennes forest in Belgium, navigating around the expensive wall and rendering it almost useless.
