1917, the fourth year of the Great War, saw another year in the trenches for millions of troops mobilised in Europe. Apart from short patrols in the North Sea, the ships of the Royal Navy and Germany's imperial navy remained in port. However, the enemy submarines were in operation intensively. In March, three American ships were sunk in one day, finally bringing the United States to the brink of war. President Woodrow Wilson made an impassioned speech to Congress, which voted for war. At the same time, Russia was in turmoil, with revolution breaking out in Petrograd, Moscow and other cities. While the Russians sued for peace with Germany and Austria-Hungary, from June onward, American soldiers began to flood into France at the rate of 300,000 a month. The Austro-Hungarians ended the year almost defeated, while the Germans knew that they had the opportunity for one final push for victory before they too would have to succumb to the weight of numbers of American troops landing at Brest and St Nazaire. The year also saw Lawrence of Arabia help the Arabs attack the Turks, the life-sucking mud of Passchendaele, the massed tank battle of Cambrai and multiple battles of the Isonzo on the border of Italy and Austria-Hungary. John Christopher and Campbell McCutcheon tell the story of 1917 at war using many rare and often unpublished images, showing the full horror of the conflict, as well as its impact on the everyday person.