Wikipedia:Selected anniversaries/April 15
- 769 – The Lateran Council concluded proceedings intended to rectify abuses in the papal electoral process that had led to the elevation of the antipopes Constantine II and Philip.
- 1912 – More than 1,500 people died after the passenger liner RMS Titanic sank as a result of colliding with an iceberg (pictured) southeast of Newfoundland.
- 1952 – The B-52 Stratofortress, a long-range, subsonic, jet-powered, strategic bomber operated by the United States Air Force for most of the aircraft's history, made its first flight.
- 1989 – A human crush during an FA Cup semi-final match between Liverpool and Nottingham Forest at Hillsborough Stadium in Sheffield, England, caused 96 deaths, making it the worst disaster in British sporting history.