World War II (1944): Overlord and Bagration

A global industrial war, 1939-1945, that killed tens of millions and remade borders, law and nuclear politics. World War II opened in Europe when Germany invaded Poland on 1 September 1939, after a decade of Japanese war in China that many historians date from the 1937 Marco Polo Bridge clash. The Axis of Germany, Italy and Japan faced a widening Allied coalition led by the United Kingdom, the Soviet Union, the United States and China.

Scholarly tallies of the dead cluster around 70-85 million, a majority civilians, with the Soviet Union and China bearing the largest national losses. The conflict fused industrial total war, the Holocaust and other genocides, strategic bombing, and the first combat use of nuclear weapons at Hiroshima and Nagasaki in August 1945.

Surrender ceremonies in May and September 1945 did not restore the 1930s map. Occupation, the United Nations Charter, partitioned Germany and Korea, and a bipolar nuclear order followed. Anglophone memory still treats the war as the century's defining just-war story, even as scholarship stresses imperial continuities and the China theatre.