World War II (1941): Barbarossa and Pearl Harbor

A war of coalitions, industry and occupation The Second World War was not one campaign but overlapping wars in Europe, Asia, Africa and at sea, bound by alliance diplomacy and factory output. Japan's war in China and Italy's wars in Africa preceded the European general war. Germany's attack on the Soviet Union in June 1941 and Japan's strike on Pearl Harbor on 7 December 1941 fused those wars into a single global contest.

Lend-Lease, the Atlantic Charter and later the United Nations Declaration (1 January 1942) turned a set of bilateral fights into a coalition with shared -- if unequal -- aims. Detroit, the Urals, the Ruhr, Osaka and the Midlands became as decisive as any river crossing. Shipping, oil, aluminium and ball bearings set the tempo of offensives.

Codebreaking at Bletchley Park and Station HYPO, radar, and the B-29 and V-2 programmes show how laboratories entered the order of battle without turning this page into a weapons manual. Nazi rule in Europe organised plunder, slave labour and the Holocaust: about six million Jews murdered, alongside millions of other targeted civilians. Japanese occupation in China and Southeast Asia produced mass death through massacre, famine and forced labour.