Galileo Galilei discovered Callisto, the fourth moon of Jupiter.
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Serial killer Jeffrey Dahmer changed his plea from not guilty to guilty but insane.
Walt Disney's Mickey Mouse comic strip was published for the first time.
German composer Richard Wagner completed 'Parsifal' – one of his most famous operas.
Instruments used to observe Venus found two-thirds of the planet's southern hemisphere brightened after aerosols were triggered on an 'astronomical' scale.
Center left-wing Independent Labour Party was formed in Britain with Keir Hardie as the leader.
