| 1845–1958 | Germany [earth sciences] | German naturalist and explorer Alexander von Humboldt lays the basis of modern geography with the publication of Kosmos/Cosmos, in which he arranges geographic knowledge in a systematic fashion. |
| 1925 | USA [clothing and fashion] | The flapper dress, which features a drop waist, becomes a popular women's style in the USA. |
| 1925 | [fiction] | The English writer Ivy Compton-Burnett publishes her novel Pastors and Masters. |
| 1925 | [fiction] | The US writer F Scott Fitzgerald publishes his novel The Great Gatsby. |
| 1925 | [fiction] | The novel Der Prozess/The Trial by the Bohemian-born German writer Franz Kafka is published posthumously. |
| 1925 | [fiction] | The English writer Virginia Woolf publishes her novel Mrs Dalloway. |
| 1925 | [fiction] | The US writer Sinclair Lewis publishes his novel Arrowsmith. |
| 1925 | USA [jazz] | The US jazz trumpeter, singer, and composer Louis ‘Satchmo’ Armstrong begins recording with his group, The Hot Five, in Chicago, Illinois. |
| 1925 | [literature and language] | The English writer Virginia Woolf publishes The Common Reader, a collection of essays. |
| 1925 | USA [agriculture] | The US Census Bureau reports that there are 75,000 fewer farms in the USA than in 1920. |
| c. 1925 | [births and deaths] | Idi Amin (Dada Oumee), president of Uganda 1971–79, who tortured and murdered between 100,000 and 300,000 Ugandans during his presidency, born in Koboko, Uganda. |
| 1925 | USA [biology] | US geneticists Thomas Hunt Morgan, Alfred Sturtevant, and Calvin Blackman Bridges publish the results of their genetic experiments with the fruit fly Drosophila melanogaster, showing that genes can be mapped onto chromosomes. |
| 1925 | Austria [chemistry] | Austrian physicist Wolfgang Pauli discovers the exclusion principle, which accounts for the electronic structure of the atom and the chemical properties of the elements. Pauli's exclusion principle states that no two electrons can occupy the same state or configuration, which relates quantum theory to the observed properties of atoms. |
| 1925 | Monaco [opera] | The opera L'Enfant et les sortilèges/The Spellbound Child, a ‘lyrical fantasy’ by the French composer Maurice Ravel, is first performed, in Monte Carlo, Monaco. The story is by the French writer Colette, the choreography by the Russian choreographer George Balanchine. |
| 1925 | Germany [opera] | The opera Wozzeck by the Austrian composer Alban Berg is first performed, in Berlin, Germany. It is based on the play Woyzeck, published in 1836 by the German writer Georg Büchner. |
| 1925 | [orchestral music] | The US composer Aaron Copland completes his choral work The House on the Hill and his orchestral work Music for the Theater. |
| 1925 | [painting] | The German artist Otto Dix paints Three Prostitutes on the Street. |
| 1925 | [painting] | The Russian artist Chaim Soutine paints Carcass of Beef. |
| 1925 | [poetry] | The US writer E E Cummings publishes his poetry collections XLI Poems and &. |
| 1925 | [poetry] | The Italian writer Eugenio Montale publishes his poetry collection Ossi di seppia/Cuttlefish Bones. |
| 1925 | [political theory] | English political scientist Harold Laski publishes A Grammar of Politics. |
| 1925 | USA [motor vehicles] | The first motel in the USA opens in California. |
| 1925 | [technology] | The Scottish electrical engineer John Logie Baird transmits the first television images of recognizable human faces. |
| 16 January 1925 | USSR [political events] | Leon Trotsky, outmanoeuvred by Joseph Stalin in his battle for the leadership of the USSR, is dismissed from the chairmanship of the Revolutionary Military Council. |
| 21 February 1925 | USA [magazines] | The first issue of the magazine New Yorker, featuring fiction, humor, and cartoons, appears in the USA, edited by Harold Ross. |
| 12 March 1925 | [births and deaths] | Sun Zhong Shan (Sun Yat-sen), leader of the Chinese Nationalist Party (Guomindang) which overthrew the Manchu dynasty, first president of the Republic of China 1911–12, and de facto ruler 1923–25, dies in Beijing, China (58). |
| 28 April 1925 | United Kingdom [banking and finance] | Britain returns sterling to the gold standard (linking the value of the pound to the Bank of England's gold reserves) at the prewar level of US $4.86, an act deemed necessary by politicians to maintain London, England, as an international centre of finance, but which leads to increasing difficulties for British industry. |
| 1 May 1925 | Cyprus, UK [colonies and mandate] | Cyprus is declared a British crown colony (having been occupied in 1914). |
| 19 May 1925 | [births and deaths] | Malcolm X, US black militant leader, born in Omaha, Nebraska (–1965). |
| 10 July 1925 | USSR [newspapers] | The Tass (Telegrafnoe Agentsvo Sovetsovo Soyuza) press agency is founded in the USSR. |
| 3 October 1925 | [births and deaths] | Gore Vidal, US novelist, playwright, and essayist, born in West Point, New Hampshire. |
| 5 October - 16 October 1925 | Switzerland, UK, France, Belgium, Germany, Italy [treaties] | The Locarno Conference in Switzerland drafts a treaty by which Britain, France, Belgium, Italy, and Germany guarantee Germany's western borders, and draws up lesser mutual assistance treaties to stabilize Germany's eastern borders. |
| 13 October 1925 | [births and deaths] | Margaret Thatcher, prime minister of Britain 1979–90, a Conservative, born in Grantham, Lincolnshire, England. |
| 19 October 1925 | Italy, Italian Somaliland [political events] | Italy completes the occupation of Italian Somaliland in east Africa (part of present-day Somalia), making it a protectorate. |
| 13 December 1925 | Persia [political events] | The nationalist army officer Reza Khan becomes shah of Persia (modern Iran). |
