20 December 586

Pablo Picasso's Portrait of Suzanne Bloch was stolen from the São Paulo Museum of Art before being recovered about three weeks later.

Portugal transferred the sovereignty over Macau, which it had administered since the mid–16th century, to China.

Mandated by the Dayton Agreement that ended the Bosnian War, the NATO-led Implementation Force (troops pictured) began peacekeeping operations in Bosnia and Herzegovina.

American Airlines Flight 965 crashed into a mountain in Buga, Colombia, killing 159 of the 163 people on board.

Twelve-year-old Jonelle Matthews disappeared from her home in Greeley, Colorado; her body was not discovered until 2019.

NBC aired the American football match between the New York Jets and the Miami Dolphins without announcers.

Experimental Breeder Reactor I near Arco, Idaho, U.S., became the world's first electricity-generating nuclear power plant when it became able to illuminate four 200-watt light bulbs.

Led by George Cathcart, British troops defeated Basuto and Taung forces at the Battle of Berea in present-day Lesotho, leading to an offer of peace from King Moshoeshoe I.

Attempting to form an alliance with the Mongol Empire, Louis IX of France met with two of their envoys while en route to the Seventh Crusade.

Six people are killed and over 200 are injured when an anti-Islam activist drives a car into a crowd at a Christmas market in Magdeburg, Germany.

A mass stabbing occurs in a primary school in Zagreb, Croatia, in which a 7-year-old pupil is killed and six more are injured by a knife-wielding 19-year-old male.

The United States Space Force becomes the first new branch of the United States Armed Forces since 1947.

Aerosucre Flight 157 crashes during takeoff from Germán Olano Airport in Puerto Carreño, Colombia, killing five people.

Elizabeth II becomes the oldest monarch in the history of the United Kingdom, surpassing Queen Victoria, who lived for 81 years and 243 days.

The Portrait of Suzanne Bloch (1904), by the Spanish artist Pablo Picasso, and O Lavrador de Café by Brazilian modernist painter Cândido Portinari, are stolen from the São Paulo Museum of Art in Brazil. Both will be recovered a few weeks later.

A gang of thieves steal £26.5 million worth of currency from the Donegall Square West headquarters of Northern Bank in Belfast, Northern Ireland, United Kingdom, one of the largest bank robberies in British history.

Macau is handed over to China by Portugal.

American Airlines Flight 965, a Boeing 757, crashes into a mountain 50 km north of Cali, Colombia, killing 159 of the 163 people on board.

A Missouri court sentences the Palestinian militant Zein Isa and his wife Maria to death for the honor killing of their daughter Palestina.

The United States invasion of Panama deposes Manuel Noriega.

War on drugs: The United Nations agrees upon and promulgates the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances, one of three major drug control treaties currently in force.

In the worst peacetime sea disaster, the passenger ferry Doña Paz sinks after colliding with the oil tanker MT Vector in the Tablas Strait of the Philippines, killing an estimated 4,000 people (1,749 official).

Pope John Paul II announces the creation of World Youth Day.

The Summit Tunnel fire, one of the largest transportation tunnel fires in history, burns after a freight train carrying over one million liters of gasoline derails near the town of Todmorden, England, in the Pennines.