1721 – Sir Robert Walpole enters office as the first Prime Minister of the United Kingdom under King George I.
1818 – The United States Congress adopts the flag of the United States with 13 red and white stripes and one star for each state (then 20).
1850 – Los Angeles, California is incorporated as a city.
1949 – Twelve nations sign the North Atlantic Treaty creating the North Atlantic Treaty Organisation.
1958 – The CND Peace Symbol displayed in public for the first time in London.
1964 – The Beatles occupy the top five positions on the Billboard Hot 100 pop chart.
1968 – Martin Luther King, Jr. is assassinated by James Earl Ray at a motel in Memphis, Tennessee.
1969 – Dr. Denton Cooley implants the first temporary artificial heart.
1973 – The World Trade Center in New York is officially dedicated.
1975 – Microsoft is founded as a partnership between Bill Gates and Paul Allen.
1994 – Marc Andreessen and Jim Clark found Netscape Communications Corporation under the name “Mosaic Communications Corporation”.
2007 – 15 British Royal Navy personnel held in Iran are released by the Iranian President. (wikipedia)