Watch History of World War I: America Goes Over (1970) : Full Movie Online Free Lasting four long years, from 1914 to 1918, World War I isn't called the Great War for no reason: It stands in history as the most "armed" conflict ever, with more troops in battle than in any other. Witness American soldiers making their way to the European continent in 1917, where they marched shoulder to shoulder with their allies Russia, France and Britain and gave testament to their commitment to democracy.