The world wars of 1914–18 and 1939–45 were global conflicts between opposing military alliances. They were the largest conflicts in human history and involved many nations across the globe. The Allies—Great Britain and her Empire, the United States, the Soviet Union and France—fought against the Axis Powers of Nazi Germany, Fascist Italy and Imperial Japan.

The long-term origins of the war grew out of the fact that the major capitalist powers of the time were beginning to lose the ability to generate wealth from domestic industrial production. As a result, they were seeking to acquire colonies—places without industry that would allow them to export raw materials for development into the global market. At the outset of the war, Britain and France, chiefly, represented countries with large colonial holdings.

During the summer of 1914, diplomatic incidents raised tensions and the two competing sets of powers formed into distinct groups: the Central Powers—Germany, Austria-Hungary and Turkey—on one side, and the Triple Entente—France, Russia and Britain—on the other.

The Allied forces defeated the Axis Powers in Europe, which included victory in North Africa—an important step in clearing Germany and Italy from the continent. The Allies then invaded Japan, triggering a chain of events that led to the end of the war at 11am on 11 November 1918 in Compiegne, France. This ended the conflict that was known as “the war to end all wars.” It spawned a second global conflict that became known as World War II.