On October 1, 1989, Denmark became the first modern country to legally recognize same-sex unions.
On October 2, 1967, Thurgood Marshall was sworn in as the first African-America U.S. Supreme Court Justice.
On October 3, 1990, the two former German countries of East and West Germany officially reunited to form the German Democratic Republic (German: Bundesrepublik Deutschland).
On October 4, 1636, the General Court of Plymouth Colony drafted its first legal code, and the first written law in North America.
On October 5, 1947, President Harry S. Truman made the first televised presidential address from the White House.
On October 6, 2000, President of the Federal Republic of Yugoslavia, Slobodan Milosevic, resigned from office.
On October 7, 2001, President George W. Bush announced that American troops had begun attacks against al-Qa’eda terrorist training camps and the Taliban command in Afghanistan.
On October 8, 2001, President George W. Bush issued Executive Order 13228 to create the Office of Homeland Security (OHS) and the Homeland Security Council (HSC).
On October 9, 1919, the Cincinnati Reds defeated the Chicago White Sox in what would soon be called the "Black Sox Scandal."
On October 10, 1970, Fiji became a sovereign country and gained its independence from Great Britain.
On October 11, 1923, a mail car of a Southern Pacific train was blown up and the beginning of a four year crime scene investigation began led by the "American Sherlock Holmes."
On October 12, 1974, Juan Domingo Perón was elected to his third term as President of Argentina after 18 years of exile from the country.
On October 13, 1999, a Boulder grand jury is dismissed after investigating a high profile murder case.
On October 14, 1975, the man whose gruesome actions led to the writing of The Amityville Horror went on trial for murder.
On October 15, 1966, Huey Newton and Bobby Seale founded the Black Panther Party in Oakland, California.
On October 16, 1978, Karol Wojtyla was elected pope of the Roman Catholic Church by the papal conclave and he assumed the name of Pope John Paul II.
On October 17, 1931, the infamous Chicago gangster, Al Capone, was convicted of federal income tax evasion.
On October 18, 1898, U.S. military troops fighting the Spanish-American War raised the U.S. flag in Puerto Rico, and the U.S. took over Puerto Rico as a colony.
On October 19, 1960, the United States officially imposed an embargo on exports to Cuba, excluding food and medicine.
On October 20, 1803, the United States Senate approved a treaty with France that provided for what is well-known as the Louisiana Purchase.
On October 21, 1921, President Warren G. Harding condemned lynching in a speech delivered in Birmingham, Alabama.
On October 22, 1721, Peter I proclaimed himself "Emperor of Russia" — a title that indicated superiority over that of mere "king."
On October 23, 1989, President Mátyás Szurös officially declared Hungary the "Republic of Hungary" and Hungary changed from a communist to democratic state.
On October 24, 1648, the Peace of Westphalia was finalized in writing to end the Thirty Years War and created the foundation for the birth of modern Europe.
On October 25, 1973, President Richard Nixon, the 37th President of the United States, vetoed the War Powers Resolution.
On October 26, 2001, President George W. Bush signed the USA PATRIOT Act.
On October 27, 1954, Benjamin O. Davis, Jr. became the first African-American General in the United States military.
On October 28, 1919, Congress passed the Volstead Act to enforce the Eighteenth Amendment of the U.S. Constitution, known as the Prohibition Amendment.
On October 29, 1901, President William McKinley's assassin died by electrocution.
On October 30, 1831, Nat Turner was arrested for leading one of the largest slave rebellions in U.S. history.
On October 31, 1517, Martin Luther nailed 95 Theses on the door of Castle Church in Wittenberg, Germany and paved the way for the Protestant Reformation.