| 1914 |
Assassination of Archduke Franz Ferdinand; Ottoman Empire joins Central Powers; German victories on the eastern front |
| 1914–1918 |
World War I |
| 1914 |
Japan joins the Triple Entente and seizes German holdings in China |
| 1915 |
Italy joins the Triple Entente; German submarine sinks the Lusitania; Japan expands into southern Manchuria |
| 1916 |
Battles of Verdun and the Somme; Irish Easter Rebellion; German Auxiliary Service Law requires seventeen- to sixty-year-old males to work for war effort; Rasputin murdered |
| 1916–1918 |
Growth of antiwar sentiment throughout Europe |
| 1917 |
United States declares war on Germany; Bolshevik Revolution in Russia |
| 1917–1922 |
Civil war in Russia |
| 1918 |
Treaty of Brest-Litovsk; revolution in Germany |
| 1919 |
Treaty of Versailles; Freudian psychology gains popularity; Rutherford splits the atom; Bauhaus school founded |
| 1920s |
Existentialism, Dadaism, and surrealism gain prominence |
| 1923 |
French and Belgian armies occupy the Ruhr |
| 1924 |
Dawes Plan |
| 1926 |
Germany joins League of Nations |
| 1928 |
Kellogg-Briand Pact |