1. In 1871, the District of Columbia abolished slavery, nine months prior to the ratification of the 13th Amendment to the U.S. Constitution.

2. On June 10, 1912, the "motor-driven apparatus for cleaning and disinfecting sewers" was patented by District of Columbia resident and inventor Joseph W. Owens.

3. In 1935, Senator Morris Sheppard recommended that the Congress recognize the District of Columbia's ratification of the 21st Amendment, which would end Prohibition. The Congress complied the following day.

4. In 1963, President John F. Kennedy delivered a speech to the graduating class of American University in D.C., in which he called for "a peace which is based on the common desire for freedom and justice."

5. On June 10, 1967, the Washington Senators baseball team played their final game at D.C.'s RFK Stadium. The team moved to suburban Virginia after the season ended.