Legendary country musician Willie Nelson held a two-day music concert for his 90th birthday party.
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The galaxy Centaurus A was discovered by Scottish astronomer James Dunlop.
The US Army freed 32,000 concentration camp prisoners in Dachau, Germany.
Prince William and Kate Middleton tied the knot.
The Simpson's 636th episode aired, making it the longest episode count of any TV series in history.
An EF4 multiple-vortex tornado destroyed areas of two major Alabama cities: Tuscaloosa and Birmingham.
