<P> In April 1940, Germany invaded Denmark and Norway to protect shipments of iron ore from Sweden, which the Allies were attempting to cut off by unilaterally mining neutral Norwegian waters . Denmark capitulated after a few hours, and despite Allied support, during which the important harbour of Narvik temporarily was recaptured from the Germans, Norway was conquered within two months . British discontent over the Norwegian campaign led to the replacement of the British Prime Minister, Neville Chamberlain, with Winston Churchill on 10 May 1940 . </P> <P> Germany launched an offensive against France and, adhering to the Manstein Plan also attacked the neutral nations of Belgium, the Netherlands, and Luxembourg on 10 May 1940 . That same day British forces landed in Iceland and the Faroes to preempt a possible German invasion of the islands . The U.S., in close co-operation with the Danish envoy to Washington D.C., agreed to protect Greenland, laying the political framework for the formal establishment of bases in April 1941 . The Netherlands and Belgium were overrun using blitzkrieg tactics in a few days and weeks, respectively . The French - fortified Maginot Line and the main body of the Allied forces which had moved into Belgium were circumvented by a flanking movement through the thickly wooded Ardennes region, mistakenly perceived by Allied planners as an impenetrable natural barrier against armoured vehicles . As a result, the bulk of the Allied armies found themselves trapped in an encirclement and were beaten . The majority were taken prisoner, whilst over 300,000, mostly British and French, were evacuated from the continent at Dunkirk by early June, although abandoning almost all of their equipment . </P> <P> On 10 June, Italy invaded France, declaring war on both France and the United Kingdom . Paris fell to the Germans on 14 June and eight days later France signed an armistice with Germany and was soon 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 but the British feared the Germans would seize it, so on 3 July, the British attacked it . </P> <P> The Battle of Britain began in early July with Luftwaffe attacks on shipping and harbours . On 19 July, Hitler again publicly offered to end the war, saying he had no desire to destroy the British Empire . The United Kingdom rejected this ultimatum . The main German air superiority campaign started in August but failed to defeat RAF Fighter Command, and a proposed invasion was postponed indefinitely on 17 September . The German strategic bombing offensive intensified as night attacks on London and other cities in the Blitz, but largely failed to disrupt the British war effort . </P>

When was the first and second world war fought