- 1457 BC Battle of Megiddo: Egyptian forces of Thutmose III defeat a large Canaanite coalition under King of Kadesh. First battle recorded with a reliable account.
- 1705 Queen Anne of England knights Isaac Newton at Trinity College, Cambridge
- 1746 Jacobite Rising 1745: Battle of Culloden, the last battle on British soil: Royalist troops under the Duke of Cumberland defeat the Jacobite army.
- 1900 US Post Office issues 1st books of postage stamps
- 1917 Vladimir Lenin issues his radical "April Theses" calling for Soviets to take power during the Russian Revolution [OS Apr 4]
- 1948 Organization for European Economic Cooperation (EEC) forms in Paris
- 2003 Treaty of Accession is signed in Athens admitting 10 new member states to the European Union
Swiss scientist Dr. Albert Hofmann discovers the psychedelic effects of LSD
On April 16, 1943
- 1966 Actor and comedian Michael Palin (22) weds Helen Gibbins
- 1994 Singer Harry Connick Jr (26) weds model Jill Goodare (30) at St. Louis Cathedral in New Orleans, Louisiana
- 1996 Singer Judy Collins (57) weds industrial designer Louis Nelson (59) at Cathedral of St. John the Divine in New York City
- 2005 One Tree Hill actress Sophia Bush (23) weds actor Chad Michael Murray (24) at Hotel Casa Del Mar in Santa Monica, California
- 2005 "Survivor: All-Stars" winner Amber Mariano (26) weds The Amazing Race star Rob Mariano (29) at the Atlantis Resort on Paradise Island in the Bahamas