A war fought between the Axis Powers and the Allies, including Britain, the Soviet Union, and the USA. Having secretly rearmed Germany, Hitler occupied (1936) the Rhineland, in contravention of the Versailles Peace Settlement. In the same year the Italian fascist dictator, Benito Mussolini, joined Hitler in a Berlin‐Rome axis, and in 1937 Italy pledged support for the Anti‐Comintern Pact between Germany and Japan. In the 1938 Anschluss, Germany annexed Austria into the Third Reich, and in the same year invaded Czechoslovak Sudetenland. Hitler, having secured the Munich Pact with Chamberlain in 1938, signed the Nazi–Soviet Pact with Stalin in August 1939. Germany then felt free to invade the Polish Corridor and divide Poland between itself and the Soviet Union. Britain, which until 1939 had followed a policy of appeasement, now delivered an ultimatum to Germany demanding its withdrawal from Poland. Failure to do so would result in war. As a consequence of Germany’s refusal to withdraw Britain declared war on Germany on 3 September. In 1940 Chamberlain resigned and Winston Churchill became head of a coalition government. The Soviet Union occupied the Baltic States and attacked Finland. Denmark, parts of Norway, Belgium, the Netherlands, and three‐fifths of France fell to Germany in rapid succession, while the rest of France was established as a neutral state with its government at Vichy. A massive bombing offensive was launched against Britain, but the planned invasion of the country was postponed indefinitely after Germany failed to gain air superiority in the Battle of Britain. Pro‐Nazi governments in Hungary, Romania, Bulgaria and Slovakia now joined the Axis Powers, and Greece and Yugoslavia were overrun in March–April 1941. Hitler, breaking his pact with Stalin, invaded the Soviet Union, where his forces reached the outskirts of Moscow. Without declaring war, Japan attacked the US fleet at Pearl Harbor in December 1941, provoking the USA to enter into the war on the side of Britain. In 1942 the first Allied counter‐offensive began against Rommel in North Africa (see north african campaigns), and in 1943 Allied troops began an invasion of the Italian mainland, resulting in the overthrow of Mussolini’s government a month later. On the Eastern Front the decisive battles around Kursk and Stalingrad broke the German hold. The Allied invasion of western Europe was launched in the Normandy Campaign in June 1944 and Germany surrendered, after Hitler’s suicide in Berlin, in May 1945. The Pacific Campaigns had eliminated the Japanese navy, and the heavy strategic bombing of Japan by the USA, culminating in the atomic bombing of Hiroshima and Nagasaki on 6 and 9 August 1945, induced Japan’s surrender a month later.

The dead in World War II have been estimated at 15 million military, of which up to 2 million were Soviet prisoners‐of‐war. An estimated 35 million civilians died, with some 6 million Jews perishing in Nazi concentration camps, in mass murders in Eastern Europe. Refugees from the Soviet Union and Eastern Europe numbered many millions. The long‐term results of the war in Europe were the division of Germany, the restoration to the Soviet Union of lands lost between 1919 and 1921, together with the creation of communist buffer states along the Soviet frontier. Britain had accumulated a $20 billion debt, while in the Far East nationalist resistance forces were to ensure the decolonization of south‐east Asian countries. The USA and the Soviet Union emerged as the two largest global powers. Their wartime alliance collapsed within three years and each embarked on a programme of rearmament with nuclear capability, as the Cold War developed.