January 15 – The Moon moves into its nearest point to Earth, called perigee, at the same time as its fullest phase of the Lunar Cycle. This is the closest moon distance at 356,397 km in recent history, and the next one will be on January 1, 2257 at 356,371 km.
March 12 – Mahatma Gandhi sets off on a 200-mile protest march towards the sea with 78 followers, to protest the British monopoly on salt; more will join them during the Salt March, that ends on April 5.
March 31 – The Motion Picture Production Code ("Hays Code") is instituted in the United States, imposing strict guidelines on the treatment of sex, crime, religion and violence in films for the next 40 years.
July 19 – Georges Simenon's detective character Inspector Jules Maigret makes his first appearance in print under Simenon's own name, when the novel Pietr-le-Letton (known in English as The Strange Case of Peter the Lett) begins serialization in a French weekly magazine. Simenon will eventually write 75 novels (as well as 28 short stories) featuring the pipe-smoking Paris detective.
October 27 – Ratifications are exchanged in London on the first London Naval Treaty signed in April, modifying the Washington Naval Treaty of 1925. Its arms limitation provisions go into effect immediately, hence putting more limits on the expensive naval arms race between its five signatories (the United Kingdom, the United States, the Japanese Empire, France, and Italy.)
November 15 – Jean Harlow has her first major film role, in Howard Hughes' epic war film Hell's Angels. Her platinum hair and sensual persona cause an immediate sensation, turning her into one of the decade's most iconic and discussed film stars.
December 7 – The television station W1XAV in Boston broadcasts video and audio from the radio orchestra program The Fox Trappers. This broadcast also includes the first television commercial in the United States, an advertisement for the I. J. Fox Furriers Company, which sponsored the telecast.