1818 – The U.S. Senate ratifies the Rush-Bagot Treaty, establishing the border with Canada.
1862 – The District of Columbia Compensated Emancipation Act, A bill ending slavery in the District of Columbia becomes law.
1881 – In Dodge City, Kansas, Bat Masterson fights his last gun battle.
1908 – Natural Bridges National Monument is established in Utah.
1912 – Harriet Quimby becomes the first woman to fly an airplane across the English Channel.
1947 – Bernard Baruch first applies the term “Cold War” to describe the relationship between the United States and the Soviet Union.
1963 – Dr. Martin Luther King Jr. pens his Letter from Birmingham Jail while incarcerated for protesting against segregation.
2007 – Virginia Tech shooting: A gunman kills 32 people and injures 17 before committing suicide on the Blacksburg campus.