1788 – American Pioneers to the Northwest Territory arrive at the confluence of the Ohio and Muskingum rivers, establishing Marietta, Ohio, as the first permanent American settlement of the new United States in the Northwest Territory, and opening the westward expansion of the new country.
1805 – Lewis and Clark Expedition: The Corps of Discovery breaks camp among the Mandan tribe and resumes its journey West along the Missouri River.
1862 – American Civil War: Battle of Shiloh ends – the Union Army under General Ulysses S. Grant defeats the Confederates near Shiloh, Tennessee.
1906 – Mount Vesuvius erupts and devastates Naples.
1933 – Prohibition in the United States is repealed for beer of no more than 3.2% alcohol by weight, eight months before the ratification of the XXI amendment.
1940 – Booker T. Washington becomes the first African American to be depicted on a United States postage stamp.
1946 – Syria's independence from France is officially recognized.
1948 – The World Health Organization is established by the United Nations.
1954 – President Dwight D. Eisenhower gives his "domino theory" speech during a news conference.
1955 – Winston Churchill resigns as Prime Minister of the United Kingdom amid indications of failing health.
1967 – Film critic Roger Ebert published his very first film review in the Chicago Sun-Times.
1969 – The Internet's symbolic birth date: publication of RFC 1.
1971 – President Richard Nixon announces his decision to increase the rate of American troop withdrawals from Vietnam.
1978 – Development of the neutron bomb is canceled by President Jimmy Carter.
1983 – During STS-6, astronauts Story Musgrave and Don Peterson perform the first space shuttle spacewalk.
2001 – Mars Odyssey is launched.
2003 – U.S. troops capture Baghdad; Saddam Hussein's regime falls two days later.