March 21st

2014
Russia formally annexes Crimea amid international condemenation.
Timeline of the annexation of Crimea by the Russian Federation ...
2010
The House of Representatives passes a bill that will overhaul the American health-care system. The bill, called the Patient Protection and Affordable Care Act, will be sent to President Obama to sign into law.
Patient Protection and Affordable Care Act
2006
Jack Dorsey sends the world's first Twitter message, or tweet. The microblogging service revolutionized the communication and social networking landscape. In 2012, about 340 million tweets were posted per day.
Twitter
2000
A divided Supreme Court ruled the government lacked authority to regulate tobacco as an addictive drug.
Tobacco Master Settlement Agreement
1987
The album 'The Joshua Tree' by U2 was released.
The Joshua Tree
1985
South African Police kill at least 21 black people commemorating a similar mass shooting 25 years before. The Sharpeville massacre in 1985 had left 69 unarmed people dead. It was a turning-point in the history of South Africa.
Sharpeville massacre
1975
Ethiopia abolishes its monarchy after 3,000 years.
Ethiopian Empire
1970
Earth Day is celebrated for the first time. The first edition was limited to some cities in the United States. Today, Earth Day is observed by about 1 billion people around the world.
Earth Day
1965
Martin Luther King, Jr., led the start of a civil rights march from Selma to Montgomery, Alabama.
Selma to Montgomery marches
1963
Alcatraz Prison in San Francisco Bay, a harsh maximum security jail which once housed gangster Al Capone, closed.
1960
Police fired on demonstrators in Sharpeville, South Africa, after which the African National Congress was banned. 25 years later, a march marking the anniversary was also disrupted by police fire.
Sharpeville massacre
1952
The world's first rock and roll concert is held in Cleveland, Ohio. DJ Alan Freed presented the concert, which was closed down after only one song because of over-crowding.
Moondog Coronation Ball
1943
A plot to assassinate Adolf Hitler by suicide bomb fails. German Wehrmacht officer, Rudolf von Gersdorff, failed to blow up the dictator but managed to defuse his bombs just before they went off and avoid suspicion.
Rudolf Christoph Freiherr von Gersdorff
1918
Germany launched the Somme offensive during World War I, hoping to break through the Allied line before American reinforcements could arrive.
Spring Offensive
1871
Journalist Henry M. Stanley began his trek to find the missionary and explorer David Livingstone.
Henry Morton Stanley
1804
The French civil code, the Code Napoleon, was officially put forth.
Napoleonic Code
1790
Thomas Jefferson took office as America's first secretary of state.
Thomas Jefferson
1685
Composer Johann Sebastian Bach was born in Eisenach, Germany.
Johann Sebastian Bach
1556
The Archbishop of Canterbury, Thomas Cranmer, was burned at the stake as a heretic.
Thomas Cranmer
1349
3,000 Jews killed in Black Death riots in Efurt, Germany.
Erfurt massacre (1349)