1940

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.
c. 1931–c. 1940	[aircraft]	Aeroplanes undergo radical changes; they become streamlined, are made almost entirely of metal, acquire controllable-pitch propellers, have air-cooled engines and retractable landing gear, and passengers and crew are protected in soundproofed and insulated cabins.
c. 1931–c. 1940	[technology]	The development of facsimile machines is made possible with the discovery of a dry chemical copying process.
1940	USA [television]	The Columbia Broadcasting System (CBS) demonstrates its colour-television system, making the world's first broadcast in colour from the Chrysler Building, New York City. The system is based on a three-colour rotating disc developed by US engineer Peter Goldmark.
1940	USA, Russia [political theory]	The US writer and critic Edmund Wilson publishes To the Finland Station, a study of the thinkers who helped to create the Russian Revolution.
1940	France [Protestantism]	The ecumenical community at Taizé, near Cluny, France, is founded by brother Roger Schutz of the Protestant French Reformed Church. The aim is to foster Christian unity.
1940	world [statistics and demography]	The population of the world is estimated at 2.229 billion.
1940–1949	USA [statistics and demography]	Immigration into the USA for the period 1940–49 stands at 856,608.
1940	UK [statistics and demography]	The populations figures for the United Kingdom are (in millions): England 39.2; Wales 2.5; Scotland 4.9; Ireland/Northern Ireland 1.3.
1940	UK [technology]	British scientists John Turon Randall and Henry Albert Boot develop the cavity magnetron, which can generate high power at high frequencies (20,000 watts at 3,000 megahertz), making centimetric radar practical for the first time. The resulting smaller radar antennae make airborne radar a practicality.
c. 1940	UK [horse-racing]	A restricted sports programme is permitted in Britain during the war.Horse racing takes place at a small number of courses. The Football League is divided into eight regional divisions. Football and rugby internationals are played between the Home Countries.
1940	USA [human rights]	The US anthropologist Ruth Benedict publishes Race: Science and Politics, an attack on racism.
1940–1944	USA [everyday life]	A large-scale migration of people from rural areas of the USA to the cities creates major urban problems.
1940	England [fiction]	The English writer Graham Greene publishes his novel The Power and the Glory.
1940	USA [fiction]	The US writer Ernest Hemingway publishes his novel For Whom the Bell Tolls, set during the Spanish Civil War.
1940	Hungary, UK [fiction]	The Hungarian-born British writer Arthur Koestler publishes Darkness at Noon, set in Russia during the Stalinist purges of the 1930s.
1940	USA [fiction]	The US writer Walter van Tilburg Clark publishes his novel The Ox-Bow Incident. Based on a lynching, the novel brings considerable psychological and moral depth to the Wild West novel.
1940	UK [food and drink]	Rationing of basic foods begins in the UK, with bacon, butter, and sugar among the first items.
1940	USA [cinema and film]	Walt Disney releases the cartoon animation film Fantasia. The classical music score includes Dukas's The Sorcerer's Apprentice. Disney also releases the animated film Pinocchio in the USA.
1940	USA, England [cinema and film]	The film Rebecca is released in the USA. It stars Joan Fontaine, Laurence Olivier, George Sanders, and Judith Anderson, and is the English director Alfred Hitchcock's first Hollywood film.
1940	USA [cinema and film]	The film The Philadelphia Story, directed by George Cukor, is released in the USA, starring Cary Grant, Katharine Hepburn, and James Stewart. It is based on the play by Philip Barry.
1940	USA [cinema and film]	The US animators William Hanna and Joseph Barbera create the cartoon duo Tom (a cat) and Jerry (a mouse), who appear in their first cartoon Puss Gets the Boot.
1940	USA [welfare]	Social security payments start in the USA. The first cheque is for $22.54.
1940	UK [welfare]	People are entitled for the first time to supplementary benefits in the UK, when the Old Age and Widows' Pensions Act is introduced.
1940	USA [work and unemployment]	US unemployment stands at 8 million: this represents 14.6% of the population.
21 February 1940	UK [welfare]	Legislation is passed to entitle British women to receive an old age pension at the age of 60.
12 March 1940	USSR, Finland [World War II (1939–45)]	The Russo-Finnish war ends. Finland signs a peace treaty with the USSR, ceding the Karelian Isthmus, the shores of Lake Ladoga, the city of Viborg, and the Hango naval base. 200,000 Finns are evicted from the area.
10 April - 13 April 1940	UK, Germany, Norway [World War II (1939–45)]	Several naval battles are fought between British and German forces off the port of Narvik in northern Norway; ten German destroyers (from a total of twenty) are sunk. Their loss, added to the loss of three (out of eight) cruisers in the invasion of Norway itself severely weakens the German navy's offensive capability.
14 April - 17 April 1940	UK, Norway [World War II (1939–45)]	British forces land at Namsos (14 April), and Åndalsnes (17 April), Norway, to assist the Norwegians against the invading German forces. Units from Åndalsnes reach the city of Lillehamer (21 May) before withdrawing.
May 1940	USA [materials]	Nylon stockings are marketed in the USA by a range of manufacturers and prove an instant success; however, nylon production is shortly to be taken up with military requirements.
10 May 1940	UK, Norway [political events]	The British prime minister Neville Chamberlain resigns following criticism for the failure of the British military expedition to Norway. Winston Churchill forms a coalition government, with Lord Halifax foreign secretary and Labour members Clement Attlee as Lord Privy Seal, Albert Alexander as First Lord of the Admiralty, and Ernest Bevin as minister of labour.
10 May 1940	France [World War II (1939–45)]	German armoured forces begin to break through French and British defensive positions into northern France.
10 May - 14 May 1940	Germany, Netherlands, Belgium, Luxembourg [World War II (1939–45)]	German forces invade the Netherlands, Belgium, and Luxembourg.
14 May 1940	UK [administration]	Recruiting begins for the Local Defence Volunteers (later the Home Guard) in Britain.
26 May - 4 June 1940	Germany, France, UK, Belgium [World War II (1939–45)]	Over 338,000 British, French, and Belgian troops are evacuated from Dunkirk, France to England by an unprecedented armada of small British boats, following the German encirclement of Allied forces in northeastern France.
15 June - 17 June 1940	USSR, Estonia, Latvia, Lithuania [political events]	The USSR occupies the Baltic states of Estonia, Latvia, and Lithuania, formally incorporating them into the USSR in August.
22 June 1940	France, Germany [treaties]	France signs an armistice with Germany during World War II and is divided into two zones. The Germans occupy northern and southwestern France, and a so-called autonomous ‘Vichy’ French state is to control the remaining third of the country.
26 June - 28 June 1940	USSR, Romania, Germany [diplomacy]	The USSR demands Bessarabia and Bukovina from Romania. Romania requests German support for rejection of the demand, but the German Führer refuses. Romania cedes the territories on 27 June and they are occupied by Soviet troops on 28 June.
July 1940	UK [food and drink]	Free milk is provided in the UK for mothers and children.
3 July 1940	UK, Algeria, France [World War II (1939–45)]	Britain's Royal Navy destroys most of the French fleet at Mers el-Kebir, Algeria, to prevent them being commandeered by the Germans.
10 July - 18 August 1940	UK, Germany [World War II (1939–45)]	Bomber and fighter aircraft of the German Luftwaffe (air force) attack shipping convoys in British waters and English ports, in the first phase of the Battle of Britain.
13 August 1940	UK, Germany [World War II (1939–45)]	The German Luftwaffe (air force) makes 1,786 sorties in the Battle of Britain, against 975 by the British Royal Air Force. It is known as ‘Adler Tag’ (Eagle Day), the most intense 24 hours of the Battle of Britain, and marks the beginning of ‘Adlerangraft’ (Eagle War), a two-week attack on RAF Fighter Command's aircraft, airfields, and installations.
21 August 1940	Russia [births and deaths]	Leon Trotsky, communist theorist and activist, a leader in Russia's October Revolution of 1917, is assassinated in Coyaocán, near Mexico City, Mexico (61).
23 August 1940	UK [World War II (1939–45)]	An all-night German bombing raid on London, England, begins the period of intense bombing known as the ‘Blitz’.
24 August 1940	Australia, UK [medicine]	Australian pathologist Howard Florey and German-born British biochemist Ernst Chain develop penicillin, in Oxford, England, for general clinical use as an antibiotic, announcing their results in The Lancet.
3 September 1940	USA, UK, Newfoundland [World War II (1939–45)]	The USA sells 50 veteran destroyers to Britain for use by the Royal Navy in World War II in return for a 99-year rent-free lease of bases in Newfoundland and the Caribbean.
4 September 1940	Romania [political events]	Ion Antonescu becomes prime minister of Romania and establishes a fascist dictatorship. King Carol II abdicates in favour of his son, Michael, and flees to Switzerland with his mistress, Magda Lupescu.
25 September 1940	Norway [World War II (1939–45)]	King Haakon of Norway is deposed, and Vidkun Quisling, leader of the Norwegian Nazi Party, is appointed prime minister by the German Reichscommissioner in Norway.
27 September 1940	Germany, Italy, Japan [treaties]	Germany, Italy, and Japan sign the Tripartite Pact in Berlin, Germany, pledging mutual military and economic cooperation.
1 October 1940	USA [roads]	The first modern limited-access toll highway in the USA, the Pennsylvania Turnpike, officially opens. It creates an economic boom along its route and heralds a new era in transportation in the USA. Other states begin constructing highways soon afterwards.
23 October 1940	Brazil [births and deaths]	Pele (Edson Arantes do Nascimento), Brazilian footballer, born in Três Corações, Brazil.
24 October 1940	USA [legislation]	The 40-hour work week, declared by Congress in a 1938 law, goes into effect in the USA.
November 1940	UK [telephone services]	There are 3.3 million telephones and 8.9 million radios in use in the UK.
11 November - 12 November 1940	UK, Italy [World War II (1939–45)]	Twenty-one British Swordfish naval torpedo-bombers from the aircraft carrier HMS Illustrious attack and cripple the Italian fleet at Taranto, southeast Italy, severally damaging the battleships Conte di Cavour, Littorio, and Caio Duilio.