Charles Hard Townes 1915
- 1866 - The metric system was legalized by the U.S. Congress for the standardization of weights and measures throughout the United States.
- 1868 - The Fourteenth Amendment to the U.S. Constitution was declared in effect. The amendment guaranteed due process of law.
- 1914 - World War I officially began when Austria-Hungary declared war on Serbia.
- 1945 - A U.S. Army bomber crashed into the 79th floor of New York City's Empire State Building. 14 people were killed and 26 were injured.
- 1982 - San Francisco, CA, became the first city in the U.S. to ban handguns.
- 1998 - Bell Atlantic and GTE announced $52 billion deal that created the second-largest phone company.