Fifty-two American hostages held in Tehran for 444 days were released, minutes after Ronald Reagan was sworn in as president.

John Hinckley Jr. shot President Ronald Reagan and three others outside the Washington Hilton, sending the president into emergency surgery.

Columbia lifted off from Kennedy Space Center on STS-1, the first flight of NASA's reusable Space Shuttle program, crewed by John Young and Robert Crippen.

Mehmet Ali Ağca shot Pope John Paul II four times in St. Peter's Square, wounding him gravely but not fatally.

IBM launched the IBM PC 5150, a $1,565 machine that legitimized personal computing for business and set the industry standard architecture for decades.

Microsoft released MS-DOS 1.0 to IBM, the operating system that would launch the PC era and make Bill Gates's company a software giant.

MTV launched at 12:01 a.m. with the Buggles' 'Video Killed the Radio Star,' inaugurating an era in which music videos became central to pop culture and celebrity.

Belize became fully independent from Britain, the last mainland Central American colony to break free of European rule.

The United Nations General Assembly designated an annual International Day of Peace, later fixed permanently on September 21.