- Boxer Rebellion in China - Allied forces involving British, American, German and Japanese troops end the 56-day long siege of Europeans in Peking. The Boxers began as a patriotic society of discontented Chinese and became a popular movement against foreign, and especially Christian, influence. They were joined by renegade Chinese soldiers.
- Boer War in South Africa: Siege of Ladysmith is over when the garrison town and rail junction is relieved after 118 days.
"7 March 1900: ... Isn't the war news grand. The news of Ladysmith came through to Adelaide at about eleven on Thursday night and the row in town was something to remember I believe. The Town Hall bells were set pealing and the shindy was tremendous. All day Friday was a gala day, bands playing people processing through the town promiscuous like and everything gone mad. The enthusiasm here about everything is simply marvellous and everything is war-war-war." Maisie, Her life in her letters from 1989 to 1902, ed J Kyffin Willington, 1992 p 306-7.
- Speech is first transmitted by radio waves by Fessenden in the USA.
- First flight of Count Ferdinand von Zeppelin's air ship which is constructed from a wire-braced aluminium hull covered with a cotton cloth. It contains 16 gas cells each filled with hydrogen and is powered by two 16-horsepower engines.
- Freud writes Interpretation of Dreams.
- Viennese scientist Dr Karl Landsteiner, while investigating how blood agglutinates, identifies three different blood groups: A, B and C.