Editing Atlantic Wall (section)

==Background==
{{See also|Causes of World War II}}
World War II in Europe began on 1 September 1939, with [[Nazi Germany]]'s [[invasion of Poland]]. Two days later, the [[UK]] and [[French Third Republic|France]] declared war on Germany.{{sfn|Lightning War|2009}} Poland's geographical location, however, prevented the Allies from intervening directly.{{Citation needed|date=October 2016}} Four weeks into the attack, the Germans had successfully occupied Poland.{{sfn|Lightning War|2009}}
Less than a month after this victory, [[Adolf Hitler]] issued a directive stating that Germany must be ready for an offensive through France and the [[Low Countries]].{{sfn|Lightning War|2009}} However, the ''[[Oberkommando der Wehrmacht]]'' (German high command; OKW) was convinced that preparations would take at least until the following year. After furious arguments, Hitler reluctantly agreed to wait.{{sfn|Lightning War|2009}} In May 1940, three massive German army groups [[Battle of France|overran]] France and the Low Countries in little more than six weeks.{{sfn|Lightning War|2009}}