Modern Era
Zimmermann Telegram (1917): Germany's Secret Offer to Mexico
Its publication turned American opinion sharply against Germany and helped lead to the US declaration of war on 6 April 1917.
Region
Europe
Modern Era
Battle of Passchendaele (1917): Third Ypres and the Flanders Mud
British and Empire forces advanced about 8 km and took Passchendaele ridge at enormous cost, without the hoped-for breakthrough.
Modern Era
October Revolution (1917): Lenin and the Bolshevik Takeover
The Bolsheviks overthrew the Provisional Government and set up a Soviet government led by Lenin, leading to civil war and the Soviet state.
Modern Era
February Revolution (1917): The Fall of Tsar Nicholas II
Nicholas II abdicated, ending three centuries of Romanov rule; a Provisional Government shared power with the Petrograd Soviet.
Modern Era
Battle of Vittorio Veneto (1918): Italy's Final Victory
Decisive Italian-led victory; the Austro-Hungarian army collapsed and the Armistice of Villa Giusti ended the war in Italy.
Modern Era
Battle of Amiens (1918): The Black Day of the German Army
Allied victory; German lines were broken on the first day and the Hundred Days Offensive began.
Modern Era
Battle of Belleau Wood (1918): US Marines in World War I
American victory; the wood was cleared by 26 June at the cost of nearly 10,000 US casualties.
Modern Era
Second Battle of the Marne (1918): The Turning of the Tide
Allied victory; the German offensive failed, the Marne salient was abandoned and the strategic initiative passed to the Allies.
Modern Era
Death of the Red Baron (1918): Manfred von Richthofen
Germany's highest-scoring ace of the war was killed by a single bullet and buried by his enemies with military honours.
Modern Era
Representation of the People Act 1918: British Women Win the Vote
About 8.4 million women and some 5 million more men gained the vote, almost tripling the British electorate.
Modern Era
Meuse-Argonne Offensive (1918): America's Largest WWI Battle
American and French forces broke through the German defences between the Meuse and the Argonne and cut key railways near Sedan, contributing to Germany's defeat.
Modern Era
Hundred Days Offensive (1918): The Allied Push to Victory
The Allies drove the German army out of most of occupied France, broke the Hindenburg Line and forced Germany to ask for the armistice of 11 November 1918.