- Mar 1 1st permanent automobile license plates issued (Ct)
- Mar 1 Governor Wouters innaugrates the radio station on the Dutch Antilles
- Mar 1 US Steel raises workers' wages to $5 a day
9th Academy Awards
Mar 4 9th Academy Awards: "The Great Ziegfeld", Paul Muni & Luise Rainer wins
- Mar 7 Bucharin, Jagoda & Rykov pushed out of CPSU in USSR
King of Swing
Mar 10 Benny Goodman unofficially crowned the “King of Swing” at New York City's Paramount Theater as his band plays before exuberant sell-out crowd filled with teenagers; unable to attend nightclub performances, kids dance in the aisles
Battle of the Century
Mar 14 Battle of the Century: US comedians Fred Allen and Jack Benny meet on radio during their "feud"
- Mar 15 1st state contraceptive clinic opens in Raleigh, North Carolina
- Mar 15 First American blood bank in a hospital is opened at Cook County Hospital in Chicago, Illinois
- Mar 18 Gas explosion in school in New London, Texas: 294 die
- Mar 18 The human-powered aircraft, Pedaliante, flies 1 kilometre (0.62 miles) outside Milan.
- Mar 19 96th Grand National: With King George VI and Queen Elizabeth in attendance, aptly-named Royal Mail ridden by jockey Evan Williams wins at odds of 100/6; estimated crowd, 300,000
- Mar 19 Astronomer Fritz Zwicky publishes his research on stellar explosion in which he coins the term "supernova" and hypothesizes that they were the origin of cosmic rays
- Mar 19 Pope Pius XI publishes encyclical Divini redemptoris against communism
- Mar 20 England beats Scotland, 6-3 at Murrayfield, Edinburgh to clinch the Home Nations Rugby Championship and Triple Crown
Battle of Guadalajara
Mar 20 Franco's Republican army launch their (eventually successful) counter-offensive against Italian International Brigades fighting for the Nationalists at the Battle of Guadalajara, Spain
- Mar 21 Ponce massacre, police kill 19 at Puerto Rican Nationalist parade
- Mar 23 LA Railway Co starts using PCC streetcars
- Mar 24 Bus carrying a roller skater troupe to Cincinnati from St.Louis crashes into a bridge abutment in Salem, Illinois, killing 21 people
- Mar 24 National Gallery of Art established by Congress
- Mar 25 Italy & Yugoslavia sign non-aggression treaty (Pact of Belgrade)
- Mar 25 Lionel Conacher misses on 1st Stanley Cup penalty shot
- Mar 25 Washington Daily News is 1st US newspaper with perfumed advertising page
DiMaggio's New Bat
Mar 26 Joe DiMaggio takes Ty Cobb's advice and replaces his 40 oz bat with a 36 oz one
- Mar 26 Spinach growers of Crystal City, Texas, erect statue of Popeye
- Mar 26 William H. Hastie becomes 1st black federal judge (Virgin Islands)
- Mar 27 Feijenoord Stadion, home ground of Dutch football club Feyenoord Rotterdam and nicknamed De Kuip opens after 2 years in construction
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