1921

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.
1921	[fiction]	The English writer D H Lawrence publishes his novel Women in Love. It was privately published in the USA in 1920.
1921	[fiction]	The Italian writer Italo Svevo publishes his novel La coscienza di Zeno/The Confessions of Zeno.
1921	[cinema and film]	The film Dream Street, directed by D W Griffith, is released in the USA, starring Tyrone Power, Sr, Ralph Graves, and Carol Dempster. It is the first to feature some singing and dialogue, supplied on synchronized records.
1921	Canada [medicine]	Canadian physiologists Frederick Banting, Charles Best, and John James MacLeod isolate insulin. A diabetic patient in Toronto, Canada, receives the first insulin injection.
1921	[physics]	German physicist Max Born develops a mathematical description of the first law of thermodynamics.
1921	Italy [plays]	The play Sei personaggi in cerca d'autore/Six Characters in Search of an Author, by the Italian writer Luigi Pirandello, is first performed, in Rome, Italy.
1921	Czechoslovakia [plays]	The play R U R: Rossum's Universal Robots, by the Czech writer Karel Capek, is first performed, in Prague, Czechoslovakia. It popularizes the word ‘robot’, from the Czech word ‘robota’, meaning ‘compulsory labour’.
1921	[poetry]	The Irish writer W B Yeats publishes his poetry collection Michael Robartes and the Dancer, which includes ‘Easter 1916’ and ‘The Second Coming’.
1921	[psychology]	Swiss psychologist Carl Jung publishes Psychologische Typen/Psychological Types, in which he differentiates two personality types: extroverted and introverted.
1921	USA [public health]	The death rate in the USA is 1,163.9 per 100,000 population, compared with 1,755 in 1900.
1921	Russia [political events]	Five million people die in a famine in the Volga region of Russia, a consequence of Bolshevik food requisitioning policies and drought.
1921	[solo and chamber music]	The English composer William Walton completes his ‘entertainment’ Façade for voices and chamber ensemble. It consists of settings of poems by the English writer Edith Sitwell.
1921	Germany [other structures]	The Einstein Tower in Potsdam, Germany, designed by the German architect Erich Mendelssohn, is completed, one of the finest examples of expressionist architecture.
1921	USA [technology]	US physicist Albert Hull invents the magnetron, an oscillator that generates microwaves.
19 February 1921	USA [transport]	The US Red Cross announces that 20,000 children die in automobile accidents each year.
25 February 1921	Georgia, Russia [political events]	A Bolshevik government is established in the republic of Georgia.
28 February - 17 March 1921	Russia [political events]	A mutiny of sailors begins at Kronstadt naval base near Petrograd, Russia, in opposition to the communist government's harsh policies; it is put down by troops.
17 March 1921	Russia [political events]	At the 10th Congress of the Russian Communist Party, the Russian leader Vladimir Ilyich Lenin introduces his New Economic Policy, which restores some private business and freedom of trade; the forcible requisition of grain has led to famine and revolts.
2 April 1921	Armenia, Russia [political events]	A Bolshevik government is established in the republic of Armenia.
23 April 1921	Romania [political events]	Through a Czechoslovak-Romanian alliance Romania joins the ‘Little Entente’ (a defensive alliance of eastern European nations).
24 April 1921	Kingdom of the Serbs Croats and Slovenes, Italy [political events]	The northern Adriatic port of Fiume (Rijeka), disputed between Italy and the Kingdom of the Serbs, Croats, and Slovenes, votes to become a free city.
5 May 1921	France [clothing and fashion]	Chanel No. 5 perfume, created by perfumer Ernst Beaux, is launched.
19 May 1921	USA [work and unemployment]	The University of Chicago announces that the average college graduate earns $5,762 per year after ten years of work.
21 May 1921	[births and deaths]	Andrey Dimitriyevich Sakharov, Soviet nuclear physicist and outspoken supporter of human rights and civil liberties, born in Moscow, Russia (–1989).
7 June 1921	Romania, Kingdom of the Serbs Croats and Slovenes [political events]	An alliance is made between Romania and the Kingdom of the Serbs, Croats, and Slovenes, completing Romania's entry into the ‘Little Entente’ (a defensive alliance of eastern European nations).
2 July 1921	USA, France [boxing]	In the first ever boxing match to gross over a million dollars, more than 80,000 people in a purpose-built wooden stadium in Jersey City, USA, watch the defending US champion Jack Dempsey knock out George Carpentier of France in four rounds to retain his world heavyweight boxing title.
9 July 1921	United Kingdom [political events]	The Irish nationalist leader Eamon de Valera, on behalf of the self-declared Irish Republic, agrees a truce with the British authorities (fighting ends two days later).
21 July 1921	Spain, Morocco [wars]	Spanish troops under General Fernandez Silvestre waging a campaign against the Riffians in Morocco are defeated by troops led by Abd al-Karim; 12,000 are killed.
5 November 1921	Russia, Mongolia [treaties]	A treaty of alliance is signed between the communist governments of Mongolia and Russia following the defeat of anticommunist White Russian forces under Roman von Ungern-Sternberg.
5 November 1921	USA [everyday life]	The US president Warren G Harding declares Armistice Day (November 11, the date of the end of World War I in 1918) a national holiday.
11 November 1921	USA [World War I (1914–18)]	The Unknown Soldier, whose body has been lying in state in the Capitol rotunda in Washington, DC, is buried at Arlington National Ceremony, Virginia, as a memorial to all other unidentified US soldiers killed in World War I.
27 November 1921	[births and deaths]	Alexander Dubcek, Czechoslovak communist leader 1968–69 whose liberal policies led to the Soviet occupation of Czechoslovakia (now the Czech and Slovak Republics), born in Uhrovec, Slovakia (–1992).
6 December 1921	United Kingdom [treaties]	The British government and representatives of the Dáil Eireann sign the Anglo-Irish Treaty providing for an independent southern Ireland with dominion status (within the British Empire).
29 December 1921	Canada [political events]	Following the defeat of the Conservatives in the Canadian general election, the Liberal leader Mackenzie King is appointed prime minister and governs with support from the Progressives.