World War II included a military campaign.
The American Theater describes a series of mostly minor areas of operations during World War II . World War II . It involved the vast majority of the world 's countries -- including all of the great powers -- eventually forming two opposing military alliances : the Allies and the Axis . The war continued primarily between the European Axis powers and the coalition of the United Kingdom and the British Commonwealth , with campaigns including the North Africa and East Africa campaigns , the aerial Battle of Britain , the Blitz bombing campaign , the Balkan Campaign as well as the long-running Battle of the Atlantic .