1940

1940 was a leap year and a pivotal year in World War II. Early in the year, Germany neutralized Denmark and Norway (April), then launched invasions of the Netherlands, Belgium, Luxembourg, and France (May–June). The Allied forces were forced to retreat to Dunkirk, with the evacuation of over 338,000 troops (Dunkirk evacuation). Paris fell on June 14, and an armistice signed on June 22 led to the occupation of northern and western France and the establishment of the Vichy regime in the south. Britain withstood the Battle of Britain, a sustained air campaign that lasted from July to October 1940 and marked a key turning point as the RAF defeated the German Luftwaffe's attempts to achieve air superiority for invasion. The war spread to the Balkans: Italy invaded Greece in October 1940; Germany would later intervene in 1941. The Soviet Union and Finland concluded the Winter War with the Moscow Peace Treaty in March 1940, Finland ceding territory but preserving its independence. On September 27, 1940, Germany, Italy, and Japan formalized the Axis with the Tripartite Pact. The same year, the United States and the United Kingdom concluded the Destroyers for Bases Agreement, expanding limited aid to Britain. The year also saw the beginning of the Blitz, a sustained German bombing campaign against British cities starting in September 1940. The global conflict continued to widen, affecting political alignments and civilian life across continents.