1920
- Bubonic Plague in India
- First Commercial Radio Broadcast Aired
- Harlem Renaissance Begins
- League of Nations Established
- Prohibition Begins in the U.S.
- Pancho Villa Retires
- Women Granted the Right to Vote in U.S.
1921
- "Fatty" Arbuckle Scandal
- Extreme Inflation in Germany
- Irish Free State Proclaimed
- Lie Detector Invented
1922
- Insulin Discovered
- Kemal Atatürk Founds Modern Turkey
- Tomb of King Tut Discovered
- Michael Collins Killed in Ambush
- Mussolini Marches on Rome
- The Reader's Digest Published
1923
- Charleston Dance Becomes Popular
- Hitler Jailed After Failed Coup
- Ruhr Occupied by French and Belgian Forces
- Talking Movies Invented
- Teapot Dome Scandal
- Time Magazine Founded
1924
- First Olympic Winter Games
- J. Edgar Hoover Appointed FBI Director
- Leopold and Loeb Murder a Neighbor Out of Boredom
- V.I. Lenin Dies
1925
- Flapper Dresses in Style
- Hitler Publishes Mein Kampf
- The Scopes (Monkey) Trial
1926
- A.A. Milne Publishes Winnie-the-Pooh
- Houdini Dies After Being Punched
- Robert Goddard Fires His First Liquid-Fuel Rocket
- A Woman Swims the English Channel
1927
- Babe Ruth Makes Home-Run Record
- BBC Founded
- The First Talking Movie, The Jazz Singer
- Lindbergh Flies Solo Across the Atlantic
- Sacco and Venzetti Executed
1928
- Bubble Gum Invented
- First Mickey Mouse Cartoon
- First Oxford English Dictionary Published
- Kellogg-Briand Treaty Outlaws War
- Penicillin Discovered
- Sliced Bread Invented
