The Second World War

Germany invaded Poland in September 1939 and Britain and France declared war; by 1941 the fighting spanned three continents. The Axis — Germany, Italy, and Japan — faced the Allies, principally Britain, the Soviet Union (invaded by Germany in June 1941, having been its partner until then), and the United States (which entered after Japan attacked Pearl Harbor that December). Germany overran France in six weeks, then stalled and bled to death on the Eastern Front; Japan seized much of the Pacific and Southeast Asia before being pushed back island by island. It ended in 1945 with Germany's surrender in May and Japan's in September, after two atomic bombs. Between 70 and 85 million people died, most of them civilians — the deadliest conflict in recorded history. It finished off the European empires, left two superpowers facing each other across a divided continent, and closed with a weapon that changed what war between great powers could mean.