January
January – 4,025 suspected communists and anarchists arrested and held without trial in the United States following raids in several cities.
January 1
Babe Ruth is traded by the Red Sox for $125,000, the largest sum ever paid for a player at that time.
Bolsheviks increase troops from four divisions to twenty along the Polish border
January 7
The forces of Russian White Admiral Alexander Kolchak surrender in Krasnoyarsk. The Great Siberian Ice March ensues.
The New York State Assembly refuses to seat five duly elected Socialist assemblymen.
January 9 – Thousands of onlookers watch as "The Human Fly" George Polley climbs the Woolworth Building in New York City. He reaches the 30th floor before being arrested.
January 10 – League of Nations Covenant enters into force. On January 16 the organization holds its first council meeting, in Paris.
January 11 – The Azerbaijan Democratic Republic is recognised de facto by European powers in Versailles.[1]
January 13 – The New York Times ridicules the American rocket scientist Robert H. Goddard. The newspaper has to recant publicly on July 17, 1969 when the Apollo crew is on its mission to the Moon.
January 16
Prohibition in the United States begins with the Eighteenth Amendment to the Constitution coming into effect.
The Allies of World War I demand that the Netherlands extradite the German Kaiser Wilhelm II, who fled there in 1918.
Zeta Phi Beta Sorority, Incorporated, is founded on the campus of Howard University in Washington, D.C.
January 19 – The United States Senate votes against joining the League of Nations.
January 22 – The Australian Country Party is officially formed, led by Nelson Pollard.
January 23 – The Netherlands refuses to extradite the German Kaiser.
January 28 – El Tercio de Extranjeros, the "Regiment of Foreigners", later the Spanish Legion, is established by decree of King Alfonso XIII of Spain.
January 30 – The oldest surviving pro wrestling match on film takes place, with Joe Stecher defeating Earl Caddock.
February
February 2
Estonian War of Independence: The Tartu Peace Treaty is signed, ending the war and recognizing Estonian independence.
France occupies Memel.
Sayyid Muhammad, Khan of Khiva abdicates.
February 7 – Admiral Kolchak and Viktor Pepelyayev are executed by firing squad near Irkutsk.
February 9 – The League of Nations gives Spitzbergen to Norway.
February 10 – General Józef Haller first performs Poland's Wedding to the Sea, a symbolic celebration of the restitution of Polish access to the Baltic Sea.
February 12–24 – Conference of London: Leaders of the United Kingdom, France and Italy meet to discuss the partitioning of the Ottoman Empire.
February 13 – Switzerland rejoins the League of Nations.
February 14 – The League of Women Voters is founded in Chicago.
February 17 – A woman named Anna Anderson tries to commit suicide in Berlin and is taken to a mental hospital, where she claims she is Grand Duchess Anastasia of Russia.
February 19 – The United States Senate refuses to ratify the Treaty of Versailles.
February 20 – 1920 Gori earthquake: An earthquake hits Gori in the Democratic Republic of Georgia, killing 114.
February 21 – The island province of Marinduque in the Philippines archipelago is founded.
February 22 – In Emeryville, California, the first dog racing track to employ an imitation rabbit opens.
February 24 – Adolf Hitler presents his National Socialist Program in Munich to the German Workers' Party (Deutsche Arbeiterpartei) which renames itself as the Nazi Party (Nationalsozialistische Deutsche Arbeiterpartei).
March
March 1
Hungarian Admiral and statesman Miklós Horthy becomes the Regent of Hungary.
The United States Railroad Administration returns control of American railroads to its constituent railroad companies.
March 7 – Syrian National Congress proclaims Syria independent with Faisal I of Iraq as king.
March 10
The world's first peaceful establishment of a social democratic government takes place in Sweden. Hjalmar Branting takes over when Nils Edén resigns.
The Baylor Business Men's Club changes its name to the Baylor University Chamber of Commerce.
March 13–17 – Wolfgang Kapp and Walther von Lüttwitz's 'Kapp Putsch', an attempted coup in Germany, briefly ousts the Weimar Republic government from Berlin but fails due to public resistance and a general strike.
March 15 – The Ruhr Red Army, a communist army 60,000 men strong, is formed in Germany.
March 15–16 – Military occupation of Constantinople by British Empire forces acting for the Allied Powers against the Turkish National Movement. Retrospectively, the Grand National Assembly of Turkey regards this as the dissolution of the Ottoman regime in Istanbul. March 17 – Birthday of Bangabandhu Sheikh Mujibur Rahman, father of the nation of Bangladesh and a political leader (d. 1975)
March 18 – Greece begins using the Gregorian calendar.
March 19 – The United States Congress refuses to ratify the Treaty of Versailles.
March 23 – Admiral Miklós Horthy declares that Hungary is a monarchy without anyone on the throne.
March 25 – Irish War of Independence: British recruits to the Royal Irish Constabulary begin to arrive in Ireland. They become known from their improvised uniforms as the "Black and Tans". March 26 – The German government asks France for permission to use its own troops against the rebellious Ruhr Red Army in the French-occupied area.
March 28 – The 1920 Palm Sunday tornado outbreak hits the Great Lakes region and Deep South of the United States.
March 29 – Sir William Robertson is promoted to Field Marshal, the first man to rise from private (enlisted 1877) to the highest rank in the British Army.
April
April 2 – The German army marches to the Ruhr to fight the Ruhr Red Army.
April 4 – 1920 Palestine riots: Violence erupts between Arab and Jewish residents in Jerusalem; 9 killed, 216 injured.
April 6 – The short-lived Far Eastern Republic is declared in eastern Siberia.
April 11 – Mexican Revolution: Álvaro Obregón flees from Mexico City during a trial intended to ruin his reputation; he flees to Guerrero where he joins Fortunato Maycotte.
April 19–26 – San Remo conference: Representatives of Italy, France, the United Kingdom and Japan meet to determine the League of Nations mandates for administration of territories following partitioning of the Ottoman Empire.
April 19 – Germany and Bolshevist Russia agree to the exchange of prisoners of war.
1920 Summer Olympics
April 20
Mexican Revolution: Álvaro Obregón announces in Chilpancingo that he intends to fight against the rule of Venustiano Carranza.
The 1920 Summer Olympics open in Antwerp, Belgium. The Olympic symbols of five interlocking rings and the associated flag are first displayed at the games.
April 23 – The Grand National Assembly of Turkey is founded by Mustafa Kemal Atatürk in Ankara. It denounces the government of Sultan Mehmed VI and announces a temporary constitution.
April 24 – Polish–Soviet War: Polish and anti-Soviet Ukrainian troops attack the Red Army in Soviet Ukraine.
April 26 – The Khorezm People's Soviet Republic is officially created by Bolshevist Russia as the successor to the Khanate of Khiva.
April 28 – The Azerbaijan Soviet Socialist Republic is officially created.
May
May 2 – The first game of Negro National League baseball is played in Indianapolis, Indiana.
May 3 – A Bolshevik coup fails in the Democratic Republic of Georgia.
May 7
Polish–Soviet War: Polish troops occupy Kiev. The government of the Ukrainian People's Republic returns to the city.
Mexican Revolution: Venustiano Carranza leaves Mexico City in a large train.
Treaty of Moscow (1920): Soviet Russia recognizes independence of the Democratic Republic of Georgia only to invade the country six months later.
May 15 – Russian Revolution: Russian White soldier Maria Bochkareva is executed in Soviet Russia.
May 16
Canonization of Joan of Arc. Over 30,000 people attend the ceremony in Rome, including 140 descendants of Joan of Arc's family. Pope Benedict XV presides over the rite, for which the interior of St. Peter's Basilica in Rome is richly decorated.
A referendum in Switzerland is favorable to joining the League of Nations.
May 17
French and Belgian troops leave the cities they have occupied in Germany.
The first flight of Dutch air company KLM, from Amsterdam to London, takes place.
May 19 – Mexican Revolution: Álvaro Obregón's troops enter Mexico City.
May 20 – Mexican Revolution: Venustiano Carranza arrives in San Antonio Tlaxcalantongo. Troops of Rodolfo Herrero attack him at night and shoot him.
May 24 – Venustiano Carranza is buried in Mexico City; all of his mourning allies are arrested. Adolfo de la Huerta is elected provisional president.
May 26 – Ganja revolt: Anti-Soviet opposition in the Azerbaijan SSR launches an abortive revolt in Ganja.
May 27 – Tomáš Garrigue Masaryk becomes president of Czechoslovakia.
May 29 – Great Floods at Louth, Lincolnshire in England kill 23.
June
June 4 – Treaty of Trianon: Peace is restored between the Allied Powers and Hungary. Hungary loses 72% of its territory.
June 5 – Bolshevik Cavalry break through Polish and Ukrainian lines south of Kiev, precipitating eventual withdrawal.
June 12 – Polish–Soviet War: The Red Army retakes Kiev.
June 13
Essad Pasha Toptani, nominal ruler of Albania, is assassinated by Avni Rustemi in Paris.
The United States Post Office Department rules that children may not be sent via parcel
June 15 – A new border treaty between Germany and Denmark gives northern Schleswig to Denmark.
June 22 – Greece attacks Turkish troops.
July
July 1 – Germany declares its neutrality in the war between Poland and Soviet Russia.
July 2 – Polish–Soviet War: Red Army continues offensive into Poland.
July 7 – Arthur Meighen becomes Canada's ninth prime minister.
July 11 – In the East Prussian plebiscite the local populace decides to remain with Weimar Germany.
July 12 – Soviet–Lithuanian Peace Treaty: The Russian Soviet Federative Socialist Republic recognizes independent Lithuania.
July 13 – London County Council bars foreigners from council jobs.[citation needed]
July 19 – August 7 – The Second Congress of the Communist International takes place in Saint Petersburg and Moscow. The notorious Twenty-one Conditions are adopted.
July 20 – The United Kingdom cedes its brief control of the key Black Sea port of Batum to the Democratic Republic of Georgia.
July 22 – Polish–Soviet War: Poland sues for peace with Bolshevist Russia (refused).
July 23 – Battle of Maysalun: The French defeat the Syrian army.
July 24 – French troops occupy Damascus and depose Faisal I of Syria as king. July 26 – Mexican Revolution: Pancho Villa takes over Sabina and contacts de la Huerta to offer his conditional surrender. He signs his surrender on July 28.
July 29 – The United States Bureau of Reclamation begins construction of the Link River Dam as part of the Klamath Reclamation Project.
July 30–August 8 – 1st World Scout Jamboree held at Olympia, London. July 31
Irish-born Australian Catholic Bishop Daniel Mannix is detained onboard ship off Queenstown and prevented from landing in Ireland or from speaking in the main Irish Catholic communities elsewhere in the United Kingdom. France prohibits the sale or prescription of contraceptives.
August
August 3 – Irish War of Independence: Catholic riots in Belfast in protest at the continuing British Army presence.
August 10 – Ottoman Sultan Mehmed VI's representatives sign the Treaty of Sèvres with the Allied Powers, confirming arrangements for partitioning of the Ottoman Empire.
August 11 – Bolshevik Russia recognizes independent Latvia.
August 13–25 – Polish–Soviet War: The Red Army is defeated in the Battle of Warsaw.
August 13 – Irish War of Independence: The Restoration of Order in Ireland Act, passed by the Parliament of the United Kingdom, receives Royal Assent, providing for Irish Republican Army activists to be tried by court-martial rather than by jury in criminal courts. August 19–25 – Second Silesian Uprising: The Poles in Upper Silesia rise up against the Germans.
August 20 – The first commercial radio station in the United States, 8MK (WWJ), begins operations in Detroit. It is owned by the 'Detroit News, the first U.S. radio station owned by a newspaper.
August 26 – The Nineteenth Amendment to the United States Constitution is passed, guaranteeing women's suffrage.
September
September 5 – Presidential elections begin in Mexico.
September 8 – Gabriele D'Annunzio proclaims the Italian Regency of Carnaro in the city of Fiume.
September 16 – The Wall Street bombing: A bomb in a horse wagon explodes in front of the J. P. Morgan building in New York City, killing 38 and injuring 400.
September 17 – The National Football League is established as the American Professional Football Association.
September 20 – The first soldier joins El Tercio de Extranjeros, the "Regiment of Foreigners", later the Spanish Legion, established on January 28, in Spain; today is celebrated as the unit's anniversary. Under the command of José Millán Astray and Francisco Franco, its first duties are against Rif rebels in the Spanish protectorate in Morocco.
September 21 – Communist Party of Uruguay is founded.
September 22 – The London Metropolitan Police forms the Flying Squad, a motorised mobile detective patrol unit.
September 27 – Polish–Soviet War: Bolshevist Russia sues for peace with Poland.
September 29
The first domestic radio sets come to stores in the United States; a Westinghouse radio costs $10.
Adolf Hitler makes his first public political speech, in Austria.
October
October 3 – Prix de l'Arc de Triomphe horse race first run in Paris.
October 9 – Polish troops take Vilnius.
October 10 – Carinthian Plebiscite: A large part of Carinthia Province votes to become part of Austria rather than Yugoslavia.
October 12 – 1920 World Series: The Cleveland Indians beat the Brooklyn Dodgers to win their first World Series title.
October 14 – A peace treaty between the Soviet and the Finnish governments is concluded at Tartu.
October 16 – Polish–Soviet War: After the Polish army captures Tarnopol, Dubno, Minsk, and Dryssa, the ceasefire is enforced.
October 18 – Thousands of unemployed demonstrate in London; 50 are injured.
October 26 – Álvaro Obregón is announced the elected president of Mexico.
October 27 – The League of Nations moves its headquarters to Geneva, Switzerland.
November
November 2
United States presidential election, 1920: Republican U. S. Senator Warren G. Harding defeats Democratic Governor of Ohio James M. Cox and Socialist Eugene V. Debs, in the first national U.S. election in which women have the right to vote.
In the United States, KDKA AM of Pittsburgh (owned by Westinghouse) starts broadcasting as a commercial radio station. The first broadcast is the results of the presidential election.
November 11 – The Unknown Warrior is buried in Westminster Abbey.
November 13 – The evacuation of the White Army's last units and civilian refugees from the Crimea on board 126 ships, the remnants of the Russian Imperial Navy, to Turkey, Tunisia and the Kingdom of Serbs, Croats and Slovenes, accompanied by wide-scale civilian massacres. The total number of evacuees amounted to approximately 150,000 people, of which ~20% were civilians.
November 14 – The Edmonton Symphony Orchestra holds its first concert.
November 15 – In Geneva, the first assembly of the League of Nations is held.
November 16 – Queensland and Northern Territory Aviation Services (Qantas) is founded by Hudson Fysh and Paul McGinness.
November 17 – The council of the League of Nations accepts the constitution for the Free City of Danzig.
November 21 – Irish War of Independence: Bloody Sunday: The Irish Republican Army, on the instructions of Michael Collins, shoot dead the "Cairo gang", fourteen British undercover agents in Dublin, most in their homes. Later that day in retaliation the Auxiliary Division of the Royal Irish Constabulary open fire on a crowd at a Gaelic Athletic Association Football match in Croke Park, killing thirteen spectators and one player and wounding 60. Three men are shot this night in Dublin Castle "while trying to escape".
November 28 – Irish War of Independence: Kilmichael Ambush: The flying column of the 3rd Cork Brigade of the Irish Republican Army, led by Tom Barry, ambushes two lorries carrying men of the Auxiliary Division of the Royal Irish Constabulary at Kilmichael, County Cork, killing seventeen (with three of its men also dying), which leads to official reprisals.
December
December 5 – A referendum in Greece is favorable to the reinstatement of the monarchy.
December 10 – Irish War of Independence: Martial law is declared in Counties Cork, Kerry, Limerick and Tipperary. December 11 – The Burning of Cork in Ireland: British forces set fire to some 5 acres (20,000 m2) of the centre of Cork, including the City Hall, in reprisal attacks after a British auxiliary is killed in a guerilla ambush.
Haiyuan earthquake
December 16
Finland joins the League of Nations.
An 8.6 Richter scale Haiyuan earthquake causes a landslide in Gansu Province, China, killing 180,000.
December 15–22 – The Brussels Conference establishes a timetable for German war reparations intended to extend for over 42 years.
December 22 – The 8th Congress of Soviets of the Russian SFSR adopts the GOELRO plan, the major plan of the economical development of the country.
December 23
United Kingdom and France ratify the border between French-held Syria and British-held Palestine.
Government of Ireland Act 1920, passed by the Parliament of the United Kingdom, receives Royal Assent from George V providing for the partition of Ireland into Northern Ireland and Southern Ireland with separate parliaments, granting a measure of home rule. December 25 – The Rosicrucian Fellowship's spiritual healing temple The Ecclesia is dedicated at Mount Ecclesia, Oceanside, California.
January – 4,025 suspected communists and anarchists arrested and held without trial in the United States following raids in several cities.
January 1
Babe Ruth is traded by the Red Sox for $125,000, the largest sum ever paid for a player at that time.
Bolsheviks increase troops from four divisions to twenty along the Polish border
January 7
The forces of Russian White Admiral Alexander Kolchak surrender in Krasnoyarsk. The Great Siberian Ice March ensues.
The New York State Assembly refuses to seat five duly elected Socialist assemblymen.
January 9 – Thousands of onlookers watch as "The Human Fly" George Polley climbs the Woolworth Building in New York City. He reaches the 30th floor before being arrested.
January 10 – League of Nations Covenant enters into force. On January 16 the organization holds its first council meeting, in Paris.
January 11 – The Azerbaijan Democratic Republic is recognised de facto by European powers in Versailles.[1]
January 13 – The New York Times ridicules the American rocket scientist Robert H. Goddard. The newspaper has to recant publicly on July 17, 1969 when the Apollo crew is on its mission to the Moon.
January 16
Prohibition in the United States begins with the Eighteenth Amendment to the Constitution coming into effect.
The Allies of World War I demand that the Netherlands extradite the German Kaiser Wilhelm II, who fled there in 1918.
Zeta Phi Beta Sorority, Incorporated, is founded on the campus of Howard University in Washington, D.C.
January 19 – The United States Senate votes against joining the League of Nations.
January 22 – The Australian Country Party is officially formed, led by Nelson Pollard.
January 23 – The Netherlands refuses to extradite the German Kaiser.
January 28 – El Tercio de Extranjeros, the "Regiment of Foreigners", later the Spanish Legion, is established by decree of King Alfonso XIII of Spain.
January 30 – The oldest surviving pro wrestling match on film takes place, with Joe Stecher defeating Earl Caddock.
February
February 2
Estonian War of Independence: The Tartu Peace Treaty is signed, ending the war and recognizing Estonian independence.
France occupies Memel.
Sayyid Muhammad, Khan of Khiva abdicates.
February 7 – Admiral Kolchak and Viktor Pepelyayev are executed by firing squad near Irkutsk.
February 9 – The League of Nations gives Spitzbergen to Norway.
February 10 – General Józef Haller first performs Poland's Wedding to the Sea, a symbolic celebration of the restitution of Polish access to the Baltic Sea.
February 12–24 – Conference of London: Leaders of the United Kingdom, France and Italy meet to discuss the partitioning of the Ottoman Empire.
February 13 – Switzerland rejoins the League of Nations.
February 14 – The League of Women Voters is founded in Chicago.
February 17 – A woman named Anna Anderson tries to commit suicide in Berlin and is taken to a mental hospital, where she claims she is Grand Duchess Anastasia of Russia.
February 19 – The United States Senate refuses to ratify the Treaty of Versailles.
February 20 – 1920 Gori earthquake: An earthquake hits Gori in the Democratic Republic of Georgia, killing 114.
February 21 – The island province of Marinduque in the Philippines archipelago is founded.
February 22 – In Emeryville, California, the first dog racing track to employ an imitation rabbit opens.
February 24 – Adolf Hitler presents his National Socialist Program in Munich to the German Workers' Party (Deutsche Arbeiterpartei) which renames itself as the Nazi Party (Nationalsozialistische Deutsche Arbeiterpartei).
March
March 1
Hungarian Admiral and statesman Miklós Horthy becomes the Regent of Hungary.
The United States Railroad Administration returns control of American railroads to its constituent railroad companies.
March 7 – Syrian National Congress proclaims Syria independent with Faisal I of Iraq as king.
March 10
The world's first peaceful establishment of a social democratic government takes place in Sweden. Hjalmar Branting takes over when Nils Edén resigns.
The Baylor Business Men's Club changes its name to the Baylor University Chamber of Commerce.
March 13–17 – Wolfgang Kapp and Walther von Lüttwitz's 'Kapp Putsch', an attempted coup in Germany, briefly ousts the Weimar Republic government from Berlin but fails due to public resistance and a general strike.
March 15 – The Ruhr Red Army, a communist army 60,000 men strong, is formed in Germany.
March 15–16 – Military occupation of Constantinople by British Empire forces acting for the Allied Powers against the Turkish National Movement. Retrospectively, the Grand National Assembly of Turkey regards this as the dissolution of the Ottoman regime in Istanbul. March 17 – Birthday of Bangabandhu Sheikh Mujibur Rahman, father of the nation of Bangladesh and a political leader (d. 1975)
March 18 – Greece begins using the Gregorian calendar.
March 19 – The United States Congress refuses to ratify the Treaty of Versailles.
March 23 – Admiral Miklós Horthy declares that Hungary is a monarchy without anyone on the throne.
March 25 – Irish War of Independence: British recruits to the Royal Irish Constabulary begin to arrive in Ireland. They become known from their improvised uniforms as the "Black and Tans". March 26 – The German government asks France for permission to use its own troops against the rebellious Ruhr Red Army in the French-occupied area.
March 28 – The 1920 Palm Sunday tornado outbreak hits the Great Lakes region and Deep South of the United States.
March 29 – Sir William Robertson is promoted to Field Marshal, the first man to rise from private (enlisted 1877) to the highest rank in the British Army.
April
April 2 – The German army marches to the Ruhr to fight the Ruhr Red Army.
April 4 – 1920 Palestine riots: Violence erupts between Arab and Jewish residents in Jerusalem; 9 killed, 216 injured.
April 6 – The short-lived Far Eastern Republic is declared in eastern Siberia.
April 11 – Mexican Revolution: Álvaro Obregón flees from Mexico City during a trial intended to ruin his reputation; he flees to Guerrero where he joins Fortunato Maycotte.
April 19–26 – San Remo conference: Representatives of Italy, France, the United Kingdom and Japan meet to determine the League of Nations mandates for administration of territories following partitioning of the Ottoman Empire.
April 19 – Germany and Bolshevist Russia agree to the exchange of prisoners of war.
1920 Summer Olympics
April 20
Mexican Revolution: Álvaro Obregón announces in Chilpancingo that he intends to fight against the rule of Venustiano Carranza.
The 1920 Summer Olympics open in Antwerp, Belgium. The Olympic symbols of five interlocking rings and the associated flag are first displayed at the games.
April 23 – The Grand National Assembly of Turkey is founded by Mustafa Kemal Atatürk in Ankara. It denounces the government of Sultan Mehmed VI and announces a temporary constitution.
April 24 – Polish–Soviet War: Polish and anti-Soviet Ukrainian troops attack the Red Army in Soviet Ukraine.
April 26 – The Khorezm People's Soviet Republic is officially created by Bolshevist Russia as the successor to the Khanate of Khiva.
April 28 – The Azerbaijan Soviet Socialist Republic is officially created.
May
May 2 – The first game of Negro National League baseball is played in Indianapolis, Indiana.
May 3 – A Bolshevik coup fails in the Democratic Republic of Georgia.
May 7
Polish–Soviet War: Polish troops occupy Kiev. The government of the Ukrainian People's Republic returns to the city.
Mexican Revolution: Venustiano Carranza leaves Mexico City in a large train.
Treaty of Moscow (1920): Soviet Russia recognizes independence of the Democratic Republic of Georgia only to invade the country six months later.
May 15 – Russian Revolution: Russian White soldier Maria Bochkareva is executed in Soviet Russia.
May 16
Canonization of Joan of Arc. Over 30,000 people attend the ceremony in Rome, including 140 descendants of Joan of Arc's family. Pope Benedict XV presides over the rite, for which the interior of St. Peter's Basilica in Rome is richly decorated.
A referendum in Switzerland is favorable to joining the League of Nations.
May 17
French and Belgian troops leave the cities they have occupied in Germany.
The first flight of Dutch air company KLM, from Amsterdam to London, takes place.
May 19 – Mexican Revolution: Álvaro Obregón's troops enter Mexico City.
May 20 – Mexican Revolution: Venustiano Carranza arrives in San Antonio Tlaxcalantongo. Troops of Rodolfo Herrero attack him at night and shoot him.
May 24 – Venustiano Carranza is buried in Mexico City; all of his mourning allies are arrested. Adolfo de la Huerta is elected provisional president.
May 26 – Ganja revolt: Anti-Soviet opposition in the Azerbaijan SSR launches an abortive revolt in Ganja.
May 27 – Tomáš Garrigue Masaryk becomes president of Czechoslovakia.
May 29 – Great Floods at Louth, Lincolnshire in England kill 23.
June
June 4 – Treaty of Trianon: Peace is restored between the Allied Powers and Hungary. Hungary loses 72% of its territory.
June 5 – Bolshevik Cavalry break through Polish and Ukrainian lines south of Kiev, precipitating eventual withdrawal.
June 12 – Polish–Soviet War: The Red Army retakes Kiev.
June 13
Essad Pasha Toptani, nominal ruler of Albania, is assassinated by Avni Rustemi in Paris.
The United States Post Office Department rules that children may not be sent via parcel
June 15 – A new border treaty between Germany and Denmark gives northern Schleswig to Denmark.
June 22 – Greece attacks Turkish troops.
July
July 1 – Germany declares its neutrality in the war between Poland and Soviet Russia.
July 2 – Polish–Soviet War: Red Army continues offensive into Poland.
July 7 – Arthur Meighen becomes Canada's ninth prime minister.
July 11 – In the East Prussian plebiscite the local populace decides to remain with Weimar Germany.
July 12 – Soviet–Lithuanian Peace Treaty: The Russian Soviet Federative Socialist Republic recognizes independent Lithuania.
July 13 – London County Council bars foreigners from council jobs.[citation needed]
July 19 – August 7 – The Second Congress of the Communist International takes place in Saint Petersburg and Moscow. The notorious Twenty-one Conditions are adopted.
July 20 – The United Kingdom cedes its brief control of the key Black Sea port of Batum to the Democratic Republic of Georgia.
July 22 – Polish–Soviet War: Poland sues for peace with Bolshevist Russia (refused).
July 23 – Battle of Maysalun: The French defeat the Syrian army.
July 24 – French troops occupy Damascus and depose Faisal I of Syria as king. July 26 – Mexican Revolution: Pancho Villa takes over Sabina and contacts de la Huerta to offer his conditional surrender. He signs his surrender on July 28.
July 29 – The United States Bureau of Reclamation begins construction of the Link River Dam as part of the Klamath Reclamation Project.
July 30–August 8 – 1st World Scout Jamboree held at Olympia, London. July 31
Irish-born Australian Catholic Bishop Daniel Mannix is detained onboard ship off Queenstown and prevented from landing in Ireland or from speaking in the main Irish Catholic communities elsewhere in the United Kingdom. France prohibits the sale or prescription of contraceptives.
August
August 3 – Irish War of Independence: Catholic riots in Belfast in protest at the continuing British Army presence.
August 10 – Ottoman Sultan Mehmed VI's representatives sign the Treaty of Sèvres with the Allied Powers, confirming arrangements for partitioning of the Ottoman Empire.
August 11 – Bolshevik Russia recognizes independent Latvia.
August 13–25 – Polish–Soviet War: The Red Army is defeated in the Battle of Warsaw.
August 13 – Irish War of Independence: The Restoration of Order in Ireland Act, passed by the Parliament of the United Kingdom, receives Royal Assent, providing for Irish Republican Army activists to be tried by court-martial rather than by jury in criminal courts. August 19–25 – Second Silesian Uprising: The Poles in Upper Silesia rise up against the Germans.
August 20 – The first commercial radio station in the United States, 8MK (WWJ), begins operations in Detroit. It is owned by the 'Detroit News, the first U.S. radio station owned by a newspaper.
August 26 – The Nineteenth Amendment to the United States Constitution is passed, guaranteeing women's suffrage.
September
September 5 – Presidential elections begin in Mexico.
September 8 – Gabriele D'Annunzio proclaims the Italian Regency of Carnaro in the city of Fiume.
September 16 – The Wall Street bombing: A bomb in a horse wagon explodes in front of the J. P. Morgan building in New York City, killing 38 and injuring 400.
September 17 – The National Football League is established as the American Professional Football Association.
September 20 – The first soldier joins El Tercio de Extranjeros, the "Regiment of Foreigners", later the Spanish Legion, established on January 28, in Spain; today is celebrated as the unit's anniversary. Under the command of José Millán Astray and Francisco Franco, its first duties are against Rif rebels in the Spanish protectorate in Morocco.
September 21 – Communist Party of Uruguay is founded.
September 22 – The London Metropolitan Police forms the Flying Squad, a motorised mobile detective patrol unit.
September 27 – Polish–Soviet War: Bolshevist Russia sues for peace with Poland.
September 29
The first domestic radio sets come to stores in the United States; a Westinghouse radio costs $10.
Adolf Hitler makes his first public political speech, in Austria.
October
October 3 – Prix de l'Arc de Triomphe horse race first run in Paris.
October 9 – Polish troops take Vilnius.
October 10 – Carinthian Plebiscite: A large part of Carinthia Province votes to become part of Austria rather than Yugoslavia.
October 12 – 1920 World Series: The Cleveland Indians beat the Brooklyn Dodgers to win their first World Series title.
October 14 – A peace treaty between the Soviet and the Finnish governments is concluded at Tartu.
October 16 – Polish–Soviet War: After the Polish army captures Tarnopol, Dubno, Minsk, and Dryssa, the ceasefire is enforced.
October 18 – Thousands of unemployed demonstrate in London; 50 are injured.
October 26 – Álvaro Obregón is announced the elected president of Mexico.
October 27 – The League of Nations moves its headquarters to Geneva, Switzerland.
November
November 2
United States presidential election, 1920: Republican U. S. Senator Warren G. Harding defeats Democratic Governor of Ohio James M. Cox and Socialist Eugene V. Debs, in the first national U.S. election in which women have the right to vote.
In the United States, KDKA AM of Pittsburgh (owned by Westinghouse) starts broadcasting as a commercial radio station. The first broadcast is the results of the presidential election.
November 11 – The Unknown Warrior is buried in Westminster Abbey.
November 13 – The evacuation of the White Army's last units and civilian refugees from the Crimea on board 126 ships, the remnants of the Russian Imperial Navy, to Turkey, Tunisia and the Kingdom of Serbs, Croats and Slovenes, accompanied by wide-scale civilian massacres. The total number of evacuees amounted to approximately 150,000 people, of which ~20% were civilians.
November 14 – The Edmonton Symphony Orchestra holds its first concert.
November 15 – In Geneva, the first assembly of the League of Nations is held.
November 16 – Queensland and Northern Territory Aviation Services (Qantas) is founded by Hudson Fysh and Paul McGinness.
November 17 – The council of the League of Nations accepts the constitution for the Free City of Danzig.
November 21 – Irish War of Independence: Bloody Sunday: The Irish Republican Army, on the instructions of Michael Collins, shoot dead the "Cairo gang", fourteen British undercover agents in Dublin, most in their homes. Later that day in retaliation the Auxiliary Division of the Royal Irish Constabulary open fire on a crowd at a Gaelic Athletic Association Football match in Croke Park, killing thirteen spectators and one player and wounding 60. Three men are shot this night in Dublin Castle "while trying to escape".
November 28 – Irish War of Independence: Kilmichael Ambush: The flying column of the 3rd Cork Brigade of the Irish Republican Army, led by Tom Barry, ambushes two lorries carrying men of the Auxiliary Division of the Royal Irish Constabulary at Kilmichael, County Cork, killing seventeen (with three of its men also dying), which leads to official reprisals.
December
December 5 – A referendum in Greece is favorable to the reinstatement of the monarchy.
December 10 – Irish War of Independence: Martial law is declared in Counties Cork, Kerry, Limerick and Tipperary. December 11 – The Burning of Cork in Ireland: British forces set fire to some 5 acres (20,000 m2) of the centre of Cork, including the City Hall, in reprisal attacks after a British auxiliary is killed in a guerilla ambush.
Haiyuan earthquake
December 16
Finland joins the League of Nations.
An 8.6 Richter scale Haiyuan earthquake causes a landslide in Gansu Province, China, killing 180,000.
December 15–22 – The Brussels Conference establishes a timetable for German war reparations intended to extend for over 42 years.
December 22 – The 8th Congress of Soviets of the Russian SFSR adopts the GOELRO plan, the major plan of the economical development of the country.
December 23
United Kingdom and France ratify the border between French-held Syria and British-held Palestine.
Government of Ireland Act 1920, passed by the Parliament of the United Kingdom, receives Royal Assent from George V providing for the partition of Ireland into Northern Ireland and Southern Ireland with separate parliaments, granting a measure of home rule. December 25 – The Rosicrucian Fellowship's spiritual healing temple The Ecclesia is dedicated at Mount Ecclesia, Oceanside, California.