On March 20

Taliban militants killed nine civilians in a mass shooting at the Kabul Serena Hotel in Afghanistan.

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

The Troubles: Two children were killed by the second of two bomb attacks by the Provisional Irish Republican Army in Warrington, England.

The antiretroviral drug zidovudine became the first treatment approved by the U.S. Food and Drug Administration for HIV/AIDS.

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.

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."

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

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

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

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

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

An earthquake occurred in the Argentine province of Mendoza, causing at least 6,000 deaths and destroying most of the buildings in the province's capital city.

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

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.

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

Following the death of Pope Innocent XIII, a papal conclave convened in Rome to elect a new pope.

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