The Second World War was an unprecedented global conflict that began with the German invasion of Poland on 1 September 1939 and ended with the Japanese surrender in August 1945. It became the first war to involve every continent and, in the Pacific, warfare between continents. Most nations, most of the world's manufacturing capacity, and most of the Earth's people were directly or indirectly involved. The use of air and sea power and advancing technology made it the first conflict in which civilians were in the front line and the distinction between combatants and noncombatants was almost erased. It was also an economic struggle decided in the end not by individual or collective skill or valor but by the balance of resources available to the participants. Among its long-term consequences, it marked the swan song of European authority: Europe, for centuries the master of empires, entered the conflict with the trappings of world leadership, but by 1945 it was clear that victory had been won by the resources and manpower of the United States and the Soviet Union, and that the age of the superpowers had dawned.