the second large international war, that was fought between 1939 and 1945 Culture The war was fought between the Axis powers (Germany, Italy and Japan) and the Allies (Britain and the countries in the British Empire, France, and later the USSR and the US). Many other countries were also involved both directly and indirectly.The war started when Germany, under Adolf Hitler and the Nazis, invaded and took control of other countries and the Allies wanted to prevent German power growing in this way. Britain declared war on Germany in September 1939 when German troops entered Poland, and soon afterwards Winston Churchill, who in Britain is closely associated with the Allies' victory in the war, became the British prime minister.In 1940 Germany attacked Britain but was not successful, mainly because of the British victory in the Battle of Britain. In 1941 Germany invaded Russia and Japan attacked Pearl Harbor, an action which brought the US into the war. In 1942 Japan increased its control over several countries in Asia but was checked by US forces in the Pacific. In the same year, at the Battle of El Alamein, Allied forces began to defeat Germany and Italy in northern Africa. In 1943 the Allies took Italy and Russian forces began to advance on Germany from the east. In 1944 the Allies invaded northern Europe with the Normandy landings and began to defeat Germany in Europe. The war ended in 1945 when the Allies took control of Germany, Hitler killed himself, and Japan was defeated as a result of atom bombs being dropped on the cities of Hiroshima and Nagasaki. Germany and Japan surrendered separately in 1945.Over 50 million people were killed in the war, more than 20 million of them Russians. World War II is also remembered for the very large number of Jewish and other people killed in German concentration camps and the harsh treatment of prisoners of war captured by the Japanese.