- 1525 The Swiss Anabaptist Movement is born when Conrad Grebel, Felix Manz, George Blaurock, and a dozen others baptize each other in the home of Manz's mother in Zürich, breaking a thousand-year tradition of church-state union
- 1789 1st American novel, WH Brown's "Power of Sympathy" is published
- 1793 Louis XVI of France is executed by the guillotine in Paris, following his conviction for high treason
- 1952 Jawaharlal Nehru's Congress party wins general election in India
- 1968 The Battle of Khe Sanh - one of the most publicized and controversial battles of the Vietnam War - begins at the Khe Sanh Air Base
- 2008 Black Monday in worldwide stock markets. FTSE 100 had its biggest ever one-day points fall, European stocks closed with their worst result since 9/11, and Asian stocks drop as much as 15%.
Parisian baker and "student of medieval life" Henri Littière appears in court charged with forcing his adulterous wife Juliette to wear a chastity belt. Having committed the same offence in 1932, he was sentenced to three months in prison and fined 50 francs for cruelty to his wife
On January 21, 1934
"Sullivan Ordinance" is passed in NYC, making it illegal for a woman to smoke in public places. It was vetoed 2 weeks later by mayor George B. McClellan Jr.
On January 21, 1908
- 1966 Beatle George Harrison marries model Patti Boyd
- 1973 Actress Jane Fonda weds activist Tom Hayden
- 1975 Actress Zsa Zsa Gabor (57) weds toy inventor Jack Ryan (48) (div. 1976)
- 1989 "Falcon Crest" actor Lorenzo Lamas (31) weds actress Kathleen Kinmont (23) at the Graceland Wedding Chapel in Las Vegas
- 2015 "One Tree Hill" star Chad Michael Murray (33) weds actress Sarah Roemer (30)
- 2011 Actress Jaime Pressly (35) divorces entertainment lawyer Simran Singh (33) due to irreconcilable differences after more than 1 year of marriage