World War II (1939–45) was the deadliest conflict in history, fought between the Allied and Axis powers across Europe, Asia, Africa and the Pacific, and killing an estimated 70–85 million people. It featured strategic bombing of cities, the Holocaust, and total mobilisation of industry and population, ending with the atomic bombings of Hiroshima and Nagasaki in August 1945. Aerial bombardment flattened urban cores from London and Coventry to Warsaw, Rotterdam, Dresden, Tokyo and beyond. The war reordered global power around the United States and the Soviet Union.
It destroyed cities across Europe and Asia and drove vast postwar reconstruction, welfare-state housing and modernist replanning. The scale of rebuilding gave planners and modernist architects an unprecedented mandate to remake the urban fabric.