- Apr 1 Stanley Cup Final, Seattle Ice Arena, Seattle, WA: With Montreal Canadiens (NHL) & Seattle Metropolitans (PCHA) tied at 2-2-1, trophy not awarded due to worldwide flu epidemic
- Apr 1 The influential Bauhaus School opens in Weimar, Germany, headed by architect Walter Gropius teaching painting, sculpture, architecture, and design [1]
- Apr 3 Austria expels all Habsburgers
- Apr 5 Antwerp is officially declared the host city for the Games of the 7th Olympiad to be conducted in 1920; first post WWI Olympics
Eamon de Valera President
Apr 5 Eamon de Valera becomes President of Dail Eireann, the Irish parliament
- Apr 5 Polish Army executes 35 young Jews
- Apr 6 Bavaria proclaims itself a soviet republic
General Strike
Apr 6 Mahatma Gandhi organizes a general strike in India to protest the Rowlatt Acts, which allowed political cases to be tried without juries and internment without trial
- Apr 7 1st parcel of land is purchased for Cleveland Metroparks
- Apr 10 Mexican Revolution leader Emiliano Zapata is ambushed and shot dead by government forces in Morelos
- Apr 11 The International Labour Organization is founded.
- Apr 12 British Parliament passes a 48-hour work week with minimum wages
- Apr 13 British troops open fire on demonstrators in Amritsar, India, killing 350
- Apr 13 Establishment of the Provisional Government of the Republic of Korea
- Apr 19 André Messager's romantic opera "Monsieur Beaucaire", based on Booth Tarkington's novel, opens at the Prince's Theatre in London, England
- Apr 19 French assembly decides on 8 hour work day
- Apr 20 King Nicholas of Montenegro abdicates under duress
- Apr 20 Polish Army captures Vilno, Lithuania from Soviet Army
- Apr 21 23rd Boston Marathon won by Carl Linder in 2:29:13.4
- Apr 23 US Major League Baseball opens a reduced 140-game season
- Apr 28 1st jump with US Army Air Corps (rip-cord type) parachute (Les Irvin)
- Apr 28 American stuntman and parachute developer Leslie Irvin (23) makes first premeditated free-fall parachute jump from a plane above US the Army Air Service's McCook Field near Dayton, Ohio [1]
- Apr 30 Phillies beat Brooklyn Dodgers 9-0 in 20 innings
Admirals
Aviators
Gangsters
Generals
Industrialists
Suffragists