WHAT ALL HAPPENED APRIL TO SEPTEMBER 1920
Find out what all happened April to September 1920

A new border treaty between Germany and Denmark gives northern Schleswig to Denmark. (15. June 1920)

Two security guards are murdered during a robbery in South Braintree, Massachusetts. Anarchists Sacco and Vanzetti would be convicted of and executed for the crime, amid much controversy. (15. April 1920)

The 19th amendment to United States Constitution takes effect, giving women the right to vote. (26. August 1920)

During the U.S. Republican National Convention in Chicago, U.S. Republican Party leaders gathered in a room at the Blackstone Hotel to come to a consensus on their candidate for the U.S. presidential election, leading the Associated Press to first coin the political phrase "smoke-filled room". (11. June 1920)

World War I: Ottoman sultan Mehmed VI's representatives sign the Treaty of Sèvres that divides up the Ottoman Empire between the Allies. (10. August 1920)

The national council in Turkey denounces the government of Sultan Mehmed VI and announces a temporary constitution. (23. April 1920)

Polish–Soviet War: Battle of Warsaw, which began on August 13, ends with the Red Army's defeat. (25. August 1920)

The Soviet–Lithuanian Peace Treaty is signed. Soviet Russia recognizes independent Lithuania. (12. July 1920)

Montreal, Quebec radio station XWA broadcasts the first regularly scheduled radio programming in North America. (20. May 1920)

Polish–Soviet War: The Battle of Radzymin concludes; the Soviet Red Army is forced to turn away from Warsaw. (16. August 1920)

Two newly purchased Savoia flying boats crash in the Swiss Alps en route to Finland where they would serve with the Suomen Ilmavoimat, killing both crews. (7. September 1920)

Construction of the Link River Dam begins as part of the Klamath Reclamation Project. (29. July 1920)

The Polish Parliament establishes Silesian Voivodeship before the Polish-German plebiscite. (15. July 1920)

Polish-Soviet War: The Polish army under General Edward Rydz-Śmigły celebrates its capture of Kiev with a victory parade on Khreschatyk. (9. May 1920)

Duluth lynchings in Minnesota. (15. June 1920)

At the San Remo conference, the principal Allied Powers of World War I adopt a resolution to determine the allocation of Class "A" League of Nations mandates for administration of the former Ottoman-ruled lands of the Middle East. (25. April 1920)

The Grand National Assembly of Turkey (TBMM) is founded in Ankara. (23. April 1920)

Peru becomes a signatory to the Buenos Aires copyright treaty. (30. April 1920)

The first game of the Negro National League baseball is played in Indianapolis. (2. May 1920)

Foundation of the Spanish Legion. (20. September 1920)