The strain of swine flu known as H1N1 had its first case in the US.
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The UK issued a new 12-sided £1 coin into circulation.
Roman Emperor Valentinian I made his brother, Flavius Valens, his co-emperor.
The term ''Big Bang" was coined by Fred Hoyle in a radio interview.
The Vienna Philharmonic Orchestra performed its first concert.
A nuclear disaster occurred at Three Mile Island in Pennsylvania, US.
