1521-Holy Roman Emperor Charles V opens the Diet of Worms in Worms, Germany, which lasts until May 25 and produces the "Edict of Worms" denouncing Martin Luther
1807-London's Pall Mall becomes the first street lit by gaslight
1813-Jane Austen's "Pride and Prejudice" is published by Thomas Egerton in the United Kingdom
1819-British colonial officer Stamford Raffles lands in Singapore
1933-The name "Pakistan" is coined by Choudhry Rahmat Ali and gradually accepted by Muslims in the Indian subcontinent, who use it to push for a separate Muslim homeland in South Asia
1961-Republic of Rwanda proclaimed
1985-Charity single "We Are the World" recorded by supergroup USA for Africa (Michael Jackson, Lionel Richie, Quincy Jones, Bruce Springsteen, Stevie Wonder, and other pop stars)
1986-Space Shuttle Challenger explodes 73 seconds after liftoff from Cape Canaveral, killing all seven crew members, including Christa McAuliffe, who was to be the first teacher in space