| 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. |
| 1918–1919 | [plagues and epidemics] | A worldwide pandemic of Spanish influenza (so called because of its particular virulence in Spain) or Encephalitis lethargica (sleeping sickness) kills over 20 million people, more than were killed during the conflicts of World War I. The movement of the armed forces at the end of the war promotes its spread. |
| 1919 | [poetry] | The US-born English writer T S Eliot publishes his poetry collection Poems, which includes ‘Gerontion’. |
| 1919 | United Kingdom, France [postal services] | The first regular international civilian airmail service is set up between London, England, and Paris, France, by French aviators Maurice and Henri Farman. It is initially too expensive to catch on. |
| 1919 | United Kingdom [consumer products] | The British company Kynoch of Birmingham introduces the zip fastener, under the name the Ready Fastener, but it is some time before it catches on commercially. |
| 1919 | [physics] | New Zealand-born British physicist Ernest Rutherford splits the atom by bombarding a nitrogen nucleus with alpha particles, discovering that it ejects hydrogen nuclei (protons). It is the first artificial disintegration of an element and inaugurates the development of nuclear energy. |
| 1919 | United Kingdom [radio] | The first radio station in Britain is established at Chelmsford, Essex. Using a 6 kW transmitter, two half-hour speech and music programmes are broadcast daily. They are banned the following year for fear of commercialization. |
| 1919 | USA [sports facilities] | The world's first commercial greyhound race track with a mechanical hare is opened in Emeryville, California. |
| 1919 | Germany [architecture] | The Bauhaus school of design, architecture, and crafts is founded in Weimar, Germany, by the German architect Walter Gropius. It is transferred to Dessau in 1926. |
| 1919 | United Kingdom [motor vehicles] | W O Bentley launches the Bentley car in Britain. |
| 1919 | France [motor vehicles] | André Citroën launches the Citroën car in France. |
| 1919 | [painting] | The French artist Marcel Duchamp creates the work L H O O Q, a reproduction of the painting Mona Lisa, on which he has painted a moustache. |
| 1919 | [zoology] | Austrian zoologist Karl von Frisch proposes that bees communicate the distance and direction of nectar to each other by two types of rhythmic movements, which he calls wagging and circle dances. |
| January 1919 | USA [legislation] | The Eighteenth Amendment to the US Constitution, prohibiting the manufacture, sale, and distribution of alcoholic beverages, becomes law. |
| 4 January 1919 | Latvia, Russia [Russian Civil War (1918–20)] | The Red Army takes Riga, Latvia, as the Russian communists attempt to reconquer the Baltic states. |
| 6 January 1919 | [births and deaths] | Theodore (‘Teddy’) Roosevelt, 26th president of the USA 1901–09, a Republican, dies in Oyster Bay, New York (60). |
| 15 January 1919 | Germany [revolution] | Volunteer soldiers suppress the Spartacist rising in Berlin, Germany, in which the Spartacist leaders Karl Liebknecht and Rosa Luxemburg are arrested and shot. |
| 31 January 1919 | [births and deaths] | Jackie Robinson, US baseball player, the first black player in the major leagues, born in Cairo, Georgia (–1972). |
| 2 March 1919 | [political parties] | The Communist Third International (Comintern) is founded to encourage world revolution. The debate over affiliation to this body will mark the split between socialist and communist movements and parties. |
| 17 March 1919 | [births and deaths] | Nat ‘King’ Cole, US jazz and popular singer, born in Montgomery, Alabama (–1965). |
| 21 March 1919 | Hungary [law and government] | A soviet government is formed in Budapest, Hungary, under the revolutionary leader Béla Kun. |
| 23 March 1919 | Italy [political parties] | Benito Mussolini founds the Fasci d'Italiani di Combattimento, an Italian fascist movement. |
| 28 March 1919 | Hungary, Czechoslovakia [wars] | Hungary declares war on Czechoslovakia over disputed areas of Slovakia. |
| 4 April - 1 May 1919 | Germany [law and government] | A soviet republic is established in Bavaria, Germany, by communists, following a radicalization of politics in the wake of the assassination of Kurt Eisner. |
| 10 April 1919 | Romania, Hungary [wars] | Romania invades Hungary to prevent it attempting to retake disputed Transylvania. |
| 13 April 1919 | India [political events] | Gurkha troops of the British Army fire on a protesting crowd in northern India in what becomes known as the ‘Amritsar Massacre’, killing 379 people and wounding over 1,200 more. |
| 29 April 1919 | Greece [political events] | The Dodecanese Islands vote to return to Greece, having been under Italian rule since 1912. |
| 3 May 1919 | India, Afghanistan [wars] | War begins between British India and Afghanistan following Afghanistan's demand for complete independence. On 8 August a peace will be agreed at Rawalpindi (now in Pakistan), conceding independence. |
| 7 May 1919 | [births and deaths] | Eva Perón, unofficial Argentine political leader and wife of Juan Perón, born in Los Todos, Argentina (–1952). |
| 7 May 1919 | Germany [diplomacy] | At the Paris Peace Conference in France, the Allies present their terms to Germany without giving opportunity for negotiation. The Rhineland is to be demilitarized and semi-occupied for between 5 and 15 years, reparations are to be paid, limits will be placed on the size of Germany's armed forces, and it is to accept a ‘war guilt’ clause acknowledging responsibility for starting the European War. Germany's colonies are also disposed of, assigning German East Africa to Britain as a mandated territory of the League of Nations, and German South West Africa as a mandate under the administration of South Africa. |
| 9 May 1919 | Belgium [suffrage] | Universal suffrage is granted in Belgium. |
| 10 May - 11 June 1919 | USA [horse-racing] | Sir Barton, ridden by US jockey Johnny Loftus, wins the Kentucky Derby, Preakness, and Belmont Stakes to become the first horse to win the US Triple Crown (though the term ‘triple crown’ is not applied to this feat until 1930). |
| 26 May 1919 | Sweden [suffrage] | Women's suffrage is granted in Sweden. |
| 28 May 1919 | Armenia, Anatolia [political events] | Armenia declares its independence from Anatolia (modern Turkey). |
| 29 May 1919 | Africa [physics] | English astrophysicist Arthur Eddington and others observe the total eclipse of the Sun on Príncipe Island (West Africa), and discover that the Sun's gravity bends the light from the stars beyond the edge of the eclipsed sun, thus fulfilling predictions made according to Albert Einstein's theory of general relativity. |
| 14 June - 15 June 1919 | Canada, Ireland, United Kingdom [aircraft] | British aviators John Alcock and Arthur Whitten Brown fly, in a Vickers-Vimy twin-engined biplane, from Newfoundland to Ireland in 16 hr 12 min, winning the £10,000 prize offered by the Daily Mail for the first nonstop transatlantic flight. |
| 20 June 1919 | Germany [political events] | The German chancellor, Philip Scheidemann, resigns in opposition to the Treaty of Versailles, which dictates peace terms unfavourable to Germany. The Social Democrat Gustav Bauer forms a cabinet comprising Social Democrats, Centre Party delegates, and Democrats on 21 June. |
| 21 June 1919 | Germany, United Kingdom [political events] | German sailors scuttle the ‘Grand Fleet’ in Scapa Flow, the British naval base in the Orkney Islands where the fleet has been quartered since the end of World War I, to prevent it falling into Allied hands following the signing of the Treaty of Versailles. |
| 28 June 1919 | France [treaties] | German representatives sign the peace treaty ending the 1914–18 war in the Hall of Mirrors of the Palace of Versailles near Paris, France (for terms, see 7 May). |
| 28 June 1919 | United Kingdom, USA, France [treaties] | Britain and the USA guarantee French security in the event of an unprovoked German attack, though the US Senate later refuses to ratify the treaty. |
| 9 August 1919 | Netherlands [suffrage] | Universal suffrage is granted in the Netherlands. |
| 10 September 1919 | Austria [treaties] | Austria signs a treaty of peace with the Allies at Saint-Germain-en-Laye near Paris, France, in which Austria recognizes the independence of Poland, Czechoslovakia, Hungary, and the Kingdom of the Serbs, Croats, and Slovenes, and agrees not to ally with Germany. Its name subsequently changes from German Austria to the Republic of Austria. |
| 10 September 1919 | Germany [roads] | The ‘Avus’ autobahn opens in Berlin, Germany. The world's first controlled access motorway, it is 10 km/6.2 mi long. |
| 12 September 1919 | Italy, Kingdom of the Serbs Croats and Slovenes [wars] | The poet and nationalist Gabriele d'Annunzio leads an unofficial Italian army to seize the northern Adriatic port of Fiume before it is incorporated into the Kingdom of the Serbs, Croats, and Slovenes. |
| 22 October 1919 | Russia [Russian Civil War (1918–20)] | The Bolshevik Red Army defeats an advancing White force under General Nicolay Yudenich near Petrograd, Russia. |
| 14 November 1919 | Russia [Russian Civil War (1918–20)] | The Bolshevik Red Army takes Omsk, Russia, from the forces of Admiral Kolchak and pushes them back into Siberia. |
| 19 November 1919 | USA [treaties] | In a 55–39 vote the US Senate rejects the Treaty of Versailles, leaving the USA outside the League of Nations. |
| 20 November 1919 | Latvia, Lithuania, Germany [political events] | German troops are forced to evacuate Latvia and Lithuania under the terms of the Treaty of Versailles. |
| 27 November 1919 | Bulgaria [treaties] | The Peace of Neuilly formally ends the war between the Allies and Bulgaria, with Bulgaria recognizing the independence of the Kingdom of the Serbs, Croats, and Slovenes and agreeing to pay reparations. |
| 28 November 1919 | United Kingdom [women's rights] | In Britain, Lady Nancy Astor is elected in a by-election and becomes the first woman member of Parliament to take her seat. |
| 3 December 1919 | [births and deaths] | Pierre-Auguste Renoir, French Impressionist painter, dies in Cannes, France (78). |