Henry Miller's Theater
Apr 1 Henry Miller's Theater opens at 124 W 43rd St NYC
- Apr 1 United Kingdom: the Royal Air Force is created from the Royal Naval Air Service and the Royal Flying Corps.
- Apr 3 US House of Representatives accepts American Creed written by William Tyler
- Apr 4 Food riot in Amsterdam
- Apr 13 Electrical fire kills 38 mental patients at Oklahoma State Hospital
- Apr 14 Douglas Campbell is 1st US ace pilot (shooting down 5th German plane)
- Apr 15 22nd Boston Marathon won by Camp Devens relay team; race run as relay for 10-man military teams
France reveals Secret Peace Overtures
Apr 15 The Sixtus Affair: French Minister Georges Clémenceau publishes secret documents showing Austrian Emperor Karl made overtures of peace to France
- Apr 16 The British House of Commons passes a new Military Service Bill, taking men up to 55 years old and extending to Ireland
Speaker's Double Play
Apr 18 Cleveland center fielder Tris Speaker turns an unassisted double play
- Apr 18 The People's Council of Latvia proclaims the independence of the new country of Latvia
The Red Baron
Apr 20 Manfred von Richthofen, aka The Red Baron, shoots down his 79th and 80th victims marking his final victories before his death the following day
- Apr 21 German World War I fighter ace Baron Manfred von Richthofen aka "The Red Baron", is shot down and killed over Vaux sur Somme in France. Canadian pilot Arthur Roy Brown is credited with the kill.
- Apr 23 Dover Patrol overthrows Germany U-boat in East Sea
- Apr 23 Raid of Zeebrugge; the British navy attempts to block German vessels from leaving port by sinking obsolete ships - mostly fails
- Apr 27 Giants' 9-0 winning start & Dodgers' 0-9 losing streak are stopped
- Apr 29 Tris Speaker ties career outfield record of 4 unassisted double plays
- Apr 30 Orange Nassau soccer team forms in Groningen
Admirals
Aviators
Gangsters
Generals
Industrialists
Suffragists