The alignment of the Central Powers along an axis through central Europe and the Near East gave them the advantage of ‘interior lines of communication’, enabling them to switch and redeploy more rapidly than their opponents, mitigating the disadvantage of having to fight on two fronts. Globally, Britain and France’s powerful navies conferred command of the seas, and access to trade with their vast colonial empires, and crucially, the United States. Japan’s early entry on the Allied side averted any threat to the Allies from the east. British and French colonial troops would make an important contribution to the European war effort, while Germany’s more recently established colonies became the basis for effective, but strategically negligible, guerrilla campaigns. German U-Boats neutralized Allied commercial access for large periods, but the sinking of American shipping triggered the entry of the United States to the war, effectively sealing the fate of the Central Powers.