The strain of swine flu known as H1N1 had its first case in the US.
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The world's first weightlifting championship took place in London, England.
An Imperial Airways passenger aircraft crashed in Belgium, killing all fifteen on board.
The Treaty of Florence was signed, which ended the war between the French Republic and the Kingdom of Naples.
Frenchman Henri Fabre flew the world's first seaplane in Martinique, France.
Roman Emperor Valentinian I made his brother, Flavius Valens, his co-emperor.