Timeline

20th century

1. April 15, 1912★★★★★

   Sinking of the Titanic

   RMS Titanic sinks in the North Atlantic on her maiden voyage after striking an iceberg; more than 1,500 people die.

   DisasterTechnology· United Kingdom
2. April 6, 1917★★★★★

   United States enters World War I

   The US Congress declares war on the German Empire, bringing the United States into World War I on the Allied side.

   War· United States, Germany
3. August 18, 1920★★★★★

   Nineteenth Amendment grants US women the vote

   The Nineteenth Amendment is ratified, prohibiting denial of the right to vote on the basis of sex in the United States.

   Politics· United States
4. January 1922★★★★★

   Insulin first used to treat diabetes

   In Toronto, insulin isolated by Frederick Banting's team is first injected into a diabetic patient, turning a fatal disease into a manageable one.

   ScienceDisease· Canada
5. May 20, 1927 – May 21, 1927★★★★★

   Lindbergh's solo transatlantic flight

   Charles Lindbergh flies solo and nonstop from New York to Paris in the Spirit of St. Louis.

   TechnologyExploration· United States, France
6. October 6, 1927★★★★★

   The Jazz Singer premieres

   The Jazz Singer, the first feature-length film with synchronised dialogue, premieres in New York, launching the era of talking pictures.

   CultureArtTechnology· United States
7. 1929★★★★★

   Hubble shows the universe is expanding

   Edwin Hubble publishes the relation between galaxies' distances and recession velocities, evidence that the universe is expanding.

   Science· United States
8. January 15, 1929★★★★★

   Birth of Martin Luther King Jr.

   Martin Luther King Jr., leader of the American civil rights movement, is born in Atlanta, Georgia.

   Birth· United States
9. October 24, 1929 – October 29, 1929★★★★★

   Wall Street Crash of 1929

   The New York stock market collapses in late October, heralding the Great Depression that spreads around the world.

   Economy· United States
10. February 18, 1930★★★★★

    Discovery of Pluto

    Clyde Tombaugh discovers Pluto at Lowell Observatory; in 2006 it is reclassified as a dwarf planet.

    Science· United States
11. March 4, 1933★★★★★

    Franklin D. Roosevelt takes office and launches the New Deal

    Franklin D. Roosevelt becomes president and launches the New Deal programs in response to the Great Depression.

    PoliticsEconomy· United States
12. December 7, 1941★★★★★

    Attack on Pearl Harbor

    The Imperial Japanese Navy launches a surprise attack on the US naval base at Pearl Harbor, Hawaii, bringing the United States into World War II.

    War· United States, Japan
13. July 16, 1945★★★★★

    Trinity nuclear test

    The United States detonates the world's first nuclear weapon in the New Mexico desert as part of the Manhattan Project.

    ScienceTechnology· United States
14. February 1946★★★★★

    ENIAC unveiled

    ENIAC, the first programmable general-purpose electronic digital computer, is unveiled to the public at the University of Pennsylvania.

    Technology· United States
15. March 5, 1946★★★★★

    Churchill's "Iron Curtain" speech

    At Fulton, Missouri, Winston Churchill declares that an "iron curtain" has descended across Europe, a symbolic marker of the early Cold War.

    Politics· United Kingdom, United States
16. December 1947★★★★★

    Invention of the transistor

    John Bardeen, Walter Brattain and William Shockley at Bell Labs build the first working transistor, the foundation of modern electronics.

    TechnologyScience· United States
17. April 3, 1948★★★★★

    Marshall Plan

    The United States enacts a large-scale economic aid programme to rebuild Western European economies after the Second World War.

    EconomyPolitics· United States, United Kingdom, France, Germany, Italy, Netherlands
18. April 4, 1949★★★★★

    NATO founded

    Twelve North American and Western European countries sign the North Atlantic Treaty in Washington, creating the NATO collective defence alliance.

    TreatyPolitics· United States, Canada, United Kingdom, France, Belgium, Netherlands, Luxembourg, Italy, Portugal, Norway, Denmark, Iceland
19. May 17, 1954★★★★★

    Brown v. Board of Education ruling

    The US Supreme Court rules that racial segregation in public schools is unconstitutional.

    Politics· United States
20. April 12, 1955★★★★★

    Salk polio vaccine declared safe and effective

    Results of a mass field trial show Jonas Salk's polio vaccine to be safe and effective, opening the way to mass vaccination.

    ScienceDisease· United States
21. November 1, 1955 – April 30, 1975★★★★★

    Vietnam War

    A conflict between North Vietnam and the Viet Cong on one side and South Vietnam, backed by the United States and its allies, on the other; it ends with the fall of Saigon in 1975.

    War· Vietnam, United States, Laos, Cambodia
22. December 1, 1955 – December 1956★★★★★

    Rosa Parks and the Montgomery bus boycott

    Rosa Parks is arrested for refusing to give up her seat to a white passenger, sparking a year-long bus boycott in Montgomery, Alabama.

    Politics· United States
23. 1962 – 1971★★★★★

    Operation Ranch Hand

    The US Air Force sprays herbicides, including dioxin-contaminated Agent Orange, over large areas of South Vietnam, with lasting health and environmental effects.

    WarDisaster· Vietnam, United States
24. October 16, 1962 – October 28, 1962★★★★★

    Cuban Missile Crisis

    A 13-day standoff between the United States and the Soviet Union over nuclear missiles in Cuba brings the world closest to nuclear war.

    Politics· Cuba, United States, Russia
25. August 28, 1963★★★★★

    "I Have a Dream" speech

    Martin Luther King Jr. delivers his famous speech at the Lincoln Memorial during the March on Washington for Jobs and Freedom.

    Politics· United States
26. November 22, 1963★★★★★

    Assassination of John F. Kennedy

    US President John F. Kennedy is shot and killed while riding in a motorcade in Dallas, Texas.

    PoliticsDeath· United States
27. July 2, 1964★★★★★

    Civil Rights Act of 1964

    President Lyndon B. Johnson signs the Civil Rights Act, outlawing discrimination based on race, color, religion, sex or national origin.

    Politics· United States
28. August 2, 1964 – August 7, 1964★★★★★

    Gulf of Tonkin incident

    A clash between USS Maddox and North Vietnamese torpedo boats leads Congress to pass the Gulf of Tonkin Resolution, enabling US escalation.

    WarPolitics· Vietnam, United States
29. March 2, 1965 – November 2, 1968★★★★★

    Operation Rolling Thunder

    A sustained US aerial bombing campaign against North Vietnam.

    War· Vietnam, United States
30. March 8, 1965★★★★★

    US Marines land at Đà Nẵng

    Two battalions of US Marines land at Đà Nẵng, the first American ground combat units deployed to Vietnam.

    War· Vietnam, United States
31. August 6, 1965★★★★★

    Voting Rights Act of 1965

    A federal law prohibits racial discrimination in voting, protecting the voting rights of African Americans.

    Politics· United States
32. November 14, 1965 – November 18, 1965★★★★★

    Battle of Ia Drang

    The first major battle between US Army forces and the North Vietnamese army, fought in the Central Highlands.

    War· Vietnam, United States
33. January 21, 1968 – July 9, 1968★★★★★

    Battle of Khe Sanh

    North Vietnamese forces besiege the US Marine base at Khe Sanh in Quảng Trị; US forces abandon the base in July.

    War· Vietnam, United States
34. January 30, 1968 – September 1968★★★★★

    Tet Offensive

    North Vietnamese and Viet Cong forces attack more than 100 cities and towns in the South; despite heavy losses, the offensive erodes US public support for the war.

    War· Vietnam, United States
35. March 16, 1968★★★★★

    Mỹ Lai massacre

    US soldiers of Charlie Company kill hundreds of unarmed civilians at Sơn Mỹ, Quảng Ngãi; the killings become public in 1969.

    War· Vietnam, United States
36. April 4, 1968★★★★★

    Assassination of Martin Luther King Jr.

    Martin Luther King Jr. is shot dead at the Lorraine Motel in Memphis, Tennessee, triggering riots in many American cities.

    PoliticsDeath· United States
37. October 29, 1969★★★★★

    First message sent over ARPANET

    The first message is sent between UCLA and the Stanford Research Institute over ARPANET, the precursor of the Internet.

    Technology· United States
38. 1971★★★★★

    First networked email

    Ray Tomlinson sends the first email between computers on ARPANET, choosing the @ sign to separate user and host names.

    Technology· United States
39. November 1971★★★★★

    Intel 4004, the first commercial microprocessor

    Intel introduces the 4004, the first commercially available single-chip microprocessor, paving the way for personal computers.

    Technology· United States
40. December 18, 1972 – December 29, 1972★★★★★

    Operation Linebacker II

    The United States carries out intensive B-52 bombing of Hanoi and Haiphong for twelve days, known in Vietnam as the "Điện Biên Phủ in the air".

    War· Vietnam, United States
41. January 27, 1973★★★★★

    Paris Peace Accords

    The United States, North and South Vietnam and the Provisional Revolutionary Government sign an agreement ending direct US involvement in the war.

    Treaty· Vietnam, United States, France
42. March 29, 1973★★★★★

    Last US combat troops leave Vietnam

    The last US combat units leave South Vietnam under the terms of the Paris Peace Accords.

    WarPolitics· Vietnam, United States
43. August 9, 1974★★★★★

    Nixon resigns over the Watergate scandal

    Richard Nixon becomes the first US president to resign, facing likely impeachment over the Watergate scandal.

    Politics· United States
44. September 5, 1977★★★★★

    Launch of Voyager 1

    NASA launches Voyager 1 to study Jupiter and Saturn; it later becomes the first human-made object to reach interstellar space.

    ExplorationScience· United States
45. August 12, 1981★★★★★

    IBM launches the IBM Personal Computer

    IBM introduces the IBM PC, whose architecture becomes the de facto standard for personal computers for decades.

    TechnologyEconomy· United States
46. January 1, 1983★★★★★

    ARPANET switches to TCP/IP

    ARPANET officially switches to the TCP/IP protocol suite, often regarded as the birth of the modern Internet.

    Technology· United States
47. January 1, 1994★★★★★

    NAFTA enters into force

    The North American Free Trade Agreement between the United States, Canada and Mexico takes effect, creating one of the world's largest trade blocs.

    TreatyEconomy· United States, Canada, Mexico
48. February 3, 1994★★★★★

    US lifts trade embargo on Vietnam

    President Bill Clinton announces the lifting of the US trade embargo on Vietnam.

    EconomyPolitics· Vietnam, United States
49. July 11, 1995★★★★★

    Normalisation of US–Vietnam relations

    President Bill Clinton announces the normalisation of diplomatic relations with Vietnam.

    PoliticsTreaty· Vietnam, United States
50. September 4, 1998★★★★★

    Google is founded

    Larry Page and Sergey Brin incorporate Google, which becomes the world's most widely used search engine.

    TechnologyEconomy· United States