UNESCO inscribed the Maya city of Chichen Itza, home to the great pyramid Kukulkan, as a World Heritage Site.

Chile's 1988 plebiscite result was confirmed: voters had rejected another eight-year term for dictator Augusto Pinochet, forcing a democratic transition.

F. Ross Johnson proposed a management-led leveraged buyout of RJR Nabisco, igniting the largest and most cutthroat corporate takeover battle of the 1980s.

The Morris Worm, released the previous day, spreads across thousands of computers, forcing researchers to disconnect systems and prompting the first major CFAA prosecution.

The Soviet space shuttle Buran launches unmanned, orbits Earth twice, and lands automatically—its only flight before the program's cancellation.

NSFNET established one of the earliest high-speed transatlantic network connections linking American research networks to European counterparts, a foundational step toward the modern global internet.

The World Health Organization observed the first World AIDS Day, launching an annual global campaign of awareness during the height of the epidemic's terror and stigma.

Soviet Soyuz TM-7 carrying French astronaut Jean-Loup Chrétien docked with the Mir space station, deepening Cold War-era space cooperation.

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Chile's electoral tribunal certified the 'No' victory from October's plebiscite, forcing General Augusto Pinochet to schedule democratic elections and end his dictatorship.

A terrorist bomb hidden in luggage detonated aboard Pan Am Flight 103, killing all 259 aboard and 11 people on the ground in Lockerbie, Scotland.