April 18: Independence Day in Zimbabwe (1980).
- 1506 – Construction of the current St. Peter's Basilica (interior pictured) in Vatican City, to replace the old St. Peter's Basilica built in the 4th century, began.
- 1518 – Bona Sforza was crowned as queen consort of Poland.
- 1942 – World War II: Sixteen B-25 Mitchell bombers from the aircraft carrier USS Hornet carried out the Doolittle Raid, the first Allied attack on the Japanese home islands.
- 1983 – A suicide bomber destroyed the United States Embassy in Beirut with a car bomb, killing over 60 people.
- 1988 – Iran–Iraq War: U.S. naval forces launched Operation Praying Mantis in retaliation for the Iranian mining of the Persian Gulf and the subsequent damage to the American frigate USS Samuel B. Roberts.
- 1992 – General Abdul Rashid Dostum revolted against the Democratic Republic of Afghanistan and allied with Ahmad Shah Massoud to capture the Afghan capital of Kabul.
- 1996 – Israeli forces shelled Qana, Lebanon during Operation Grapes of Wrath, killing over 100 civilians and injuring over 110 others at a UN compound.