America joined the Allied side in the First World War in April 1917 despite residual opposition to entering a European conflict. This map, part of a British propaganda campaign directed at the American public, shows the Western and Eastern fronts overlaid on the United States, underscoring the continental scale of the war. The fronts are 2,195 miles long, only 95 miles less than the distance between Chicago and San Francisco. ‘It will need every ounce of effort which they (the Allies) and their American comrades can put into the struggle to defeat the sinister aims of Prussian militarism.’