1. In 1916, the First Division of the United States Army was formed in Washington, D.C., in preparation for World War I. The division would go on to serve in France and become one of the most distinguished units in the war.

2. In 1960, John F. Kennedy and Richard Nixon participated in the first televised presidential debate in Washington, D.C. The debate was watched by over 70 million people and is considered a turning point in American political history.

3. In 1979, the Washington Metro subway system opened its first line, connecting Union Station to Silver Spring, Maryland. The system now consists of six lines and over 90 stations, serving the greater D.C. area.

4. In 2001, the United States launched air strikes against targets in Afghanistan in response to the 9/11 terrorist attacks. The strikes were launched from bases in the District of Columbia and Virginia.

5. In 2013, the Smithsonian National Museum of African American History and Culture opened its doors in Washington, D.C. The museum features exhibits and artifacts documenting the African American experience from the slave trade to modern times.