It was a modern design but assumed the sort of [[trench warfare]] that was central to [[World War I]]. In 1940 the German [[Blitzkrieg]] or lighting war strategy, outflanked the static line going around it, invading France by going through Belgium in spring 1940. | It was a modern design but assumed the sort of [[trench warfare]] that was central to [[World War I]]. In 1940 the German [[Blitzkrieg]] or lighting war strategy, outflanked the static line going around it, invading France by going through Belgium in spring 1940. |