4 December 1986

"Il Canto degli Italiani" officially became the national anthem of Italy, 66 years after it was provisionally chosen following the birth of the Italian Republic.

U.S. president George H. W. Bush ordered American troops into Somalia to help provide humanitarian aid and restore order during the ongoing Somali Civil War.

The MV Amazon Venture oil tanker starts leaking while at the port of Savannah, resulting in an oil spill of approximately 500,000 US gallons (1,900,000 L).

The English rock group Led Zeppelin officially disbanded.

Following the murder of Mayor George Moscone, Dianne Feinstein became San Francisco's first female mayor.

The Troubles: The Ulster Volunteer Force, an Ulster-loyalist paramilitary group, detonated a bomb at a Catholic-owned pub in Belfast, Northern Ireland, killing 15 people.

Indo-Pakistani War: The Indian Navy launched a successful attack against the Pakistan Navy at Karachi, sinking three ships with no Indian casualties.

Fred Hampton, the leader of the Illinois chapter of the Black Panther Party, and Mark Clark were killed in a raid by Chicago police officers in what many scholars consider an illegal assassination.

Cosmo Gordon Lang was enthroned as the Archbishop of Canterbury, the first bachelor to be appointed in 150 years.

World War I: Senior British and French figures, including prime ministers H. H. Asquith and Aristide Briand, met at Calais to discuss the future of the Salonika Front.

The Montreal Canadiens, the oldest professional ice hockey club in the world, were founded as a charter member of the National Hockey Association.

The Great Seimas of Vilnius met to discuss national concerns within Lithuania: they decided to demand wide political autonomy within the Russian Empire.

First Matabele War: A patrol of 34 British South Africa Company soldiers was ambushed and annihilated by more than 3,000 Matabele warriors.

The American brigantine Mary Celeste was found apparently abandoned under circumstances that remain unknown.

Sati, the Hindu funeral custom of a widow's self-immolation on her husband's pyre, was prohibited by Lord William Bentinck in parts of British India after years of campaigning by Ram Mohan Roy (pictured).

Jeremiah Horrocks and William Crabtree made the first successful observation of a transit of Venus (example pictured) from Earth.

Hundred Years' War: In two separate engagements in the Battle of Pontvallain (depicted), French forces wiped out an English army which had split up because of a dispute between the commanders.

Yasser Abu Shabab is assassinated near Rafah, Gaza Strip.

Semeru on the Indonesian island of Java erupts, killing at least 68 people.

The Thomas Fire starts near Santa Paula in California. It eventually became the largest wildfire in modern California history to date after burning 1,140 square kilometers (440 sq mi) in Ventura and Santa Barbara Counties.

Islamic insurgents kill three state police at a traffic circle before taking an empty school and a "press house" in Grozny. Ten state forces die with 28 injured in gun battles ending with ten insurgents killed.

Tens of thousands of people in Hong Kong protest for democracy and call on the government to allow universal and equal suffrage.

The Unity Module, the second module of the International Space Station, is launched.

Somali Civil War: President George H. W. Bush orders 28,000 U.S. troops to Somalia in Northeast Africa.