Irish Republican Army (IRA) ambushed British soldiers near Kilmichael in County Cork.
Benito Mussolini and Leandro Arpinati led squads of fighters in the melee between Fascists and Socialists in Bologna, Italy.
The Model M Postage Meter was put into commercial use.
The Communist Party of Australia (CPA) was founded in Sydney by a group inspired by the Russian Revolution.
Times Square Theater opened with a capacity of 1,032.
The Wall Street bombing took place in Manhattan, New York City.
The Nineteenth Amendment to the United States Constitution was certified, giving women the right to vote.