| 1914–1918 | 1917 |
| – World War I | – Germany resumes unrestricted submarine warfare |
| June 28, 1914 | March 1917 |
| – Serbian nationalist assassinates Archduke Francis Ferdinand | – February Revolution in Russia |
| August 1914 | April 1917 |
| – War begins | – United States enters the war |
| September 1914 | October–November 1917 |
| – Battle of the Marne; German victories on the eastern front | – Battle of Caporetto |
| October 1914 | November 1917 |
| – Ottoman Empire joins the Central Powers | – Bolshevik Revolution in Russia; Balfour Declaration on Jewish homeland in Palestine |
| 1915 | 1918 |
| – Italy joins the Triple Entente; German submarine sinks the Lusitania; Germany halts unrestricted submarine warfare | – Treaty of Brest-Litovsk; revolution in Germany |
| 1915–1918 | 1918–1920 |
| – Armenian genocide; German armies occupy large parts of east-central Europe | – Civil war in Russia |
| 1916 | 1919 |
| – Battles of Verdun and the Somme | – Treaty of Versailles; Allies invade Turkey |
| 1916–1918 | 1923 |
| – Antiwar movement spreads throughout Europe; Arab rebellion against Ottoman Empire | – Treaty of Lausanne recognizes Turkish independence |