page_title: World War II
section_title: Western Europe (1940–41)
hierarchical_section_title: World War II / Course of the war / Western Europe (1940–41)
caption_attribution_description: English: The view from the roof of St Paul's Cathedral towards the Old Baliey after the second Great Fire of London
context_page_description: World War II, also known as the Second World War, was a global war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all the great powers—forming two opposing military alliances: the Allies and the Axis. In a state of total war, directly involving more than 100 million people from more than 30 countries, the major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 70 to 85 million fatalities. Tens of millions of people died due to genocides, premeditated death from starvation, massacres, and disease. Aircraft played a major role in the conflict, including in the use of strategic bombing of population centres, and the only uses of nuclear weapons in war.
  World War II is generally considered to have begun on 1 September 1939, with the invasion of Poland by Germany and subsequent declarations of war on Germany by France and the United Kingdom.
context_section_description: In April 1940, Germany invaded Denmark and Norway to protect shipments of iron ore from Sweden, which the Allies were attempting to cut off. Denmark capitulated after a few hours, and Norway was conquered within two months despite Allied support. British discontent over the Norwegian campaign led to the appointment of Winston Churchill as Prime Minister on 10 May 1940.
  On the same day, Germany launched an offensive against France. To circumvent the strong Maginot Line fortifications on the Franco-German border, Germany directed its attack at the neutral nations of Belgium, the Netherlands, and Luxembourg. The Germans carried out a flanking manoeuvre through the Ardennes region, which was mistakenly perceived by Allies as an impenetrable natural barrier against armoured vehicles. By successfully implementing new blitzkrieg tactics, the Wehrmacht rapidly advanced to the Channel and cut off the Allied forces in Belgium, trapping the bulk of the Allied armies in a cauldron on the Franco-Belgian border near Lille. The United Kingdom was able to evacuate a significant number of Allied troops from the continent by early June, although abandoning almost all their equipment.
  On 10 June, Italy invaded France, declaring war on both France and the United Kingdom. The Germans turned south against the weakened French army, and Paris fell to them on 14 June. Eight days later France signed an armistice with Germany; it was divided into German and Italian occupation zones, and an unoccupied rump state under the Vichy Regime, which, though officially neutral, was generally aligned with Germany. France kept its fleet, which the United Kingdom attacked on 3 July in an attempt to prevent its seizure by Germany.
  The Battle of Britain began in early July with Luftwaffe attacks on shipping and harbours. The United Kingdom rejected Hitler's ultimatum, and the German air superiority campaign started in August but failed to defeat RAF Fighter Command, forcing the indefinite postponement of the proposed German invasion of Britain. The German strategic bombing offensive intensified with night attacks on London and other cities in the Blitz, but failed to significantly disrupt the British war effort and largely ended in May 1941.
  Using newly captured French ports, the German Navy enjoyed success against an over-extended Royal Navy, using U-boats against British shipping in the Atlantic. The British Home Fleet scored a significant victory on 27 May 1941 by sinking the German battleship Bismarck.
  In November 1939, the United States was taking measures to assist China and the Western Allies, and amended the Neutrality Act to allow "cash and carry" purchases by the Allies. In 1940, following the German capture of Paris, the size of the United States Navy was significantly increased. In September the United States further agreed to a trade of American destroyers for British bases. Still, a large majority of the American public continued to oppose any direct military intervention in the conflict well into 1941. In December 1940 Roosevelt accused Hitler of planning world conquest and ruled out any negotiations as useless, calling for the United States to become an "arsenal of democracy" and promoting Lend-Lease programmes of aid to support the British war effort. The United States started strategic planning to prepare for a full-scale offensive against Germany.
  At the end of September 1940, the Tripartite Pact formally united Japan, Italy, and Germany as the Axis Powers. The Tripartite Pact stipulated that any country, with the exception of the Soviet Union, which attacked any Axis Power would be forced to go to war against all three. The Axis expanded in November 1940 when Hungary, Slovakia and Romania joined. Romania and Hungary would make major contributions to the Axis war against the Soviet Union, in Romania's case partially to recapture territory ceded to the Soviet Union.
caption: London seen from St. Paul's Cathedral after the German Blitz, 29 December 1940
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