On this day: 20 March

Michael IV Autoreianos is appointed Ecumenical Patriarch of Constantinople.

The Dutch East India Company, the first company to issue stock, was established.

A fire of unknown cause broke out in Boston, Massachusetts, destroying 349 buildings.

After escaping from Elba, Napoleon enters Paris with a regular army of 140,000 and a volunteer force of around 200,000, beginning his "Hundred Days" rule.

German revolutions of 1848–49: King Ludwig I of Bavaria abdicates.

Harriet Beecher Stowe's novel Uncle Tom's Cabin, which had a profound effect on attitudes toward African Americans and slavery in the United States, was published.

The Republican Party was founded in Ripon, Wisconsin, by politicians opposing the Kansas–Nebraska Act and the expansion of slavery in the United States.

The Paris Convention for the Protection of Industrial Property is signed.

The premiere of the very first Romani language operetta is staged in Moscow, Russia.

Emperor Wilhelm II dismissed Otto von Bismarck as the chancellor of the German Empire.

With the approval of Emperor Guangxu, the Qing dynasty post office is opened, marking the beginning of a postal service in China.

The first of a series of auctions of sheep farming land in southern Patagonia takes place impacting established settlers.

Albert Einstein submits his paper, "The Foundation of the General Theory of Relativity", which establishes his general theory of relativity, to the journal Annalen der Physik.

The Upper Silesia plebiscite, mandated by the Versailles Treaty to determine a section of the border between Weimar Germany and Poland, is held.

The United States Navy commissioned its first aircraft carrier, USS Langley.

The Arts Club of Chicago hosted the opening of Pablo Picasso's first solo United States showing, entitled Original Drawings by Pablo Picasso.

Chiang Kai-shek initiated a purge of communist elements within the National Revolutionary Army in Guangzhou, China.

Germany issued an ultimatum to Lithuania, demanding the return of the Klaipėda Region under threat of invasion.

World War II: After being forced to flee the Philippines for Australia, US Army general Douglas MacArthur announced: "I came through and I shall return."

World War II: U.S. Marines made a landing on Emirau Island in the Bismarck Archipelago to develop an airbase as part of Operation Cartwheel.

With a Musicians Union ban lifted, the first telecasts of classical music in the United States, under Eugene Ormandy and Arturo Toscanini, are given on CBS and NBC.

Fujiyoshida, a city located in Yamanashi Prefecture, Japan, in the center of the Japanese main island of Honshū is founded.

The US Senate ratifies the Security Treaty between the United States and Japan.

Tunisia gains independence from France.

The precursor of the European Space Agency, ESRO (European Space Research Organisation) is established per an agreement signed on June 14, 1962.

Libby Riddles becomes the first woman to win the 1,135-mile Iditarod Trail Sled Dog Race.

Eritrean War of Independence: Having defeated the Nadew Command, the Eritrean People's Liberation Front enters the town of Afabet, victoriously concluding the Battle of Afabet.

Legoland California, the first Legoland outside of Europe, opens in Carlsbad, California, US.

Eyjafjallajökull (pictured) in Iceland began a series of volcanic events, later disrupting air travel across Europe.

Syrian civil war: The Siege of Kobanî is broken by the People's Protection Units (YPG) and Free Syrian Army (FSA), marking a turning point in the Rojava–Islamist conflict.

A solar eclipse, equinox, and a supermoon all occur on the same day.

Kassym-Jomart Tokayev is sworn in as acting president of Kazakhstan, following the resignation of long-time president Nursultan Nazarbayev.

La Plume noire, an anarchist bookstore in Lyon, is targeted by an attack of the far-right, provoking a shock in Lyon's far-left circles.