2008 – The Large Hadron Collider at CERN, described as the biggest scientific experiment in history, is powered up in Geneva, Switzerland.

1776 – The Continental Congress officially names its union of states the United States.

1791 – Washington, D.C., the capital of the United States, is named after President George Washington.

1839 – John Herschel takes the first glass plate photograph.

1940 – George Stibitz pioneers the first remote operation of a computer.

1947 – First case of a computer bug being found: A moth lodges in a relay of a Harvard Mark II computer at Harvard University.

1956 – Elvis Presley appears on The Ed Sullivan Show for the first time.

2016 – The government of North Korea conducts its fifth and reportedly biggest nuclear test. World leaders condemn the act, with South Korea calling it "maniacal recklessness".

1504 – Michelangelo's David is unveiled in Piazza della Signoria in Florence.

1892 – The Pledge of Allegiance is first recited.

1966 – The landmark American science fiction television series Star Trek premieres with its first-aired episode, "The Man Trap".

1971 – In Washington, D.C., the John F. Kennedy Center for the Performing Arts is inaugurated, with the opening feature being the premiere of Leonard Bernstein's Mass.

1974 – Watergate scandal: US President Gerald Ford signs the pardon of Richard Nixon for any crimes Nixon may have committed while in office.

1927 – The first fully electronic television system is achieved by Philo Farnsworth.

1936 – The last thylacine, a carnivorous marsupial, dies alone in its cage at the Hobart Zoo in Tasmania.

1979 – The Chrysler Corporation asks the United States government for US$1.5 billion to avoid bankruptcy.

2008 – The United States government takes control of the two largest mortgage financing companies in the US, Fannie Mae and Freddie Mac.

1992 – A group of hunters at the Stampede trail near Healy, Alaska come across a male corpse in abandoned bus, later identified as Christopher McCandless.

1698 – In an effort to Westernize his nobility, Tsar Peter I of Russia imposes a tax on beards for all men except the clergy and peasantry.

1774 – First Continental Congress assembles in Philadelphia.

1793 – French Revolution: The French National Convention initiates the Reign of Terror.

1977 – Voyager Program: NASA launches the Voyager 1 spacecraft.

Geronimo!

1882 – The Pearl Street Station in New York City becomes the first power plant to supply electricity to paying customers.

1957 – American Civil Rights Movement: Little Rock Crisis: The governor of Arkansas calls out the National Guard to prevent African American students from enrolling in Little Rock Central High School, resulting in the lawsuit Cooper v. Aaron the following year.

1998 – Google is founded by Larry Page and Sergey Brin, two PhD students at Stanford University.

1783 – American Revolutionary War: The war ends with the signing of the Treaty of Paris by the United States and the Kingdom of Great Britain.

1941 – The Holocaust: Karl Fritzsch, deputy camp commandant of the Auschwitz concentration camp, experiments with the use of Zyklon B in the gassing of Soviet POWs.

1944 – Holocaust: Diarist Anne Frank and her family are placed on the last transport train from the Westerbork transit camp to the Auschwitz concentration camp, arriving three days later.

1976 – Viking program: The American Viking 2 spacecraft lands at Utopia Planitia on Mars.

1981 – The Convention on the Elimination of All Forms of Discrimination Against Women, an international bill of rights for women, is instituted by the United Nations.

2016 – The U.S. and China, together responsible for 40% of the world's carbon emissions, both formally ratify the Paris global climate agreement.

2017 – North Korea conducts its sixth and most powerful nuclear test.

 Red_Dragon wrote:
History merely rhymes.

1945 – World War II: The Japanese Instrument of Surrender is signed by Japan and the major warring powers aboard the battleship USS Missouri in Tokyo Bay, thus marking the official end to the war.

2008 – Google launches its Google Chrome web browser.

1939 – Nazi Germany mounts a false flag attack on the Gleiwitz radio station, creating an excuse to attack Poland the following day, thus starting World War II in Europe.

1963 – The Moscow–Washington hotline between the leaders of the U.S. and the Soviet Union goes into operation.

1967 – Thurgood Marshall is confirmed as the first African American Justice of the Supreme Court of the United States.

1983 – STS-8: The Space Shuttle Challenger takes off on the first night launch of the shuttle program. Guion Bluford becomes the first African-American in space on this mission.

1911 – Ishi, considered the last Native American to make contact with European Americans, emerges from the wilderness of northeastern California.

1949 – Soviet atomic bomb project: The Soviet Union tests its first atomic bomb, known as First Lightning or Joe 1, at Semipalatinsk, Kazakhstan.

1966 – The Beatles perform their last concert before paying fans at Candlestick Park in San Francisco.

1845 – The first issue of Scientific American magazine is published.

1850 – Richard Wagner's Lohengrin premieres at the Staatskapelle Weimar.

1859 – The Carrington event is the strongest geomagnetic storm on record to strike the Earth. Electrical telegraph service is widely disrupted.

1898 – Caleb Bradham's beverage "Brad's Drink" is renamed "Pepsi-Cola".

1936 – Nazi Germany begins its mass arrests of Jehovah's Witnesses, who are interned in concentration camps.

1955 – Black teenager Emmett Till is lynched in Mississippi for whistling at a white woman, galvanizing the nascent civil rights movement.

1957 – U.S. Senator Strom Thurmond begins a filibuster to prevent the United States Senate from voting on the Civil Rights Act of 1957; he stopped speaking 24 hours and 18 minutes later. This would remain the longest speech ever conducted by a single Senator until Cory Booker spoke for 25 hours and five minutes, beginning on March 31, 2025.

1963 – March on Washington for Jobs and Freedom: Rev. Dr. Martin Luther King Jr. gives his I Have a Dream speech.

1656 – The Netherlands and the Ahanta people signed the Treaty of Butre, creating a Dutch protectorate over the country of Upper Ahanta in modern-day Ghana.

1896 – In the shortest recorded war in history, the Sultanate of Zanzibar surrendered to the United Kingdom after less than an hour of conflict.

2013 – Religious violence between Hindus and Muslims erupted in Muzaffarnagar district, Uttar Pradesh, India, leaving 62 people dead.

1859 – Petroleum is discovered in Titusville, Pennsylvania, leading to the world's first commercially successful oil well.

1883 – Eruption of Krakatoa: Four enormous explosions almost completely destroy the island of Krakatoa and cause years of climate change.

1939 – First flight of the turbojet-powered Heinkel He 178, the world's first jet aircraft.

1955 – The first edition of the Guinness Book of Records is published in Great Britain.

1956 – The nuclear power station at Calder Hall in the United Kingdom was connected to the national power grid becoming the world's first commercial nuclear power station to generate electricity on an industrial scale.