- 1791 The Constitution of May 3 (the first modern constitution in Europe) is proclaimed by the Sejm of Polish-Lithuanian Commonwealth.
- 1926 British General Strike: Trade Union Congress calls for a general strike 1 minute to midnight to support striking coal miners
- 1937 Margaret Mitchell wins Pulitzer Prize for "Gone With the Wind"
- 1945 World War II: German ship "Cap Arcona" laden with prisoners sunk by Royal Air Force in East Sea, 5,800 killed - one of largest maritime losses of life
- 1947 Japan's post-war constitution goes into effect, granting universal suffrage, stripping Emperor Hirohito of all but symbolic power and outlawing Japan's right to make war
- 1999 Stephen Hendry defeats Mark Williams 18-11 to win the World Snooker Championship for a record seventh time.
Day depicted by Spanish painter Goya in his "The Third of May", painted 1814
On May 3, 1808
First unsolicited bulk commercial e-mail ("spam") is sent by a Digital Equipment Corporation marketing representative to every ARPANET address on the US west coast
On May 3, 1978
- 1884 Mechanical engineer Frederick Winslow Taylor (28) weds Louise M. Spooner
- 1986 Actress-singer Annette Funicello (43) weds harness racing horse breeder and trainer Glen Holt
- 1991 American singer Andy Williams weds 2nd wife Debbie Hass
- 1992 Beverly Hills 90210 actress Gabrielle Carteris marries Charles Isaacs
- 1997 "Port Charles" soap opera actor Jon Lindstrom (39) weds "The Young and The Restless" actress Eileen Davidson (38) in Cambria, California