1. The Potomac River Flood of 1932: May 13, 1932, saw one of the worst natural disasters in the history of D.C. A massive flood caused by incessant rains in the Potomac River caused extensive damage to the city. The flood caused widespread devastation with the water level reaching up to 17 feet high in Georgetown.

2. The Integration of Howard University: On May 13, 1964, Howard University became the first integrated university in Washington D.C. African-American students had been protesting the segregationist policies of the university for years, and their efforts finally bore fruit when the university decided to admit students irrespective of their color.

3. The Death of Robert F. Kennedy: May 13 marks a tragic day in the history of D.C. On this day in 1968, Robert F. Kennedy, younger brother of President John F. Kennedy, was assassinated at the Ambassador Hotel in Los Angeles. Kennedy had just won the California Democratic primary election and was a leading candidate for the presidency.

4. The Washington Bullets' 1978 NBA Championship: May 13 saw the Washington Bullets, now known as the Washington Wizards, win their first NBA championship on this day in 1978. The Bullets defeated the Seattle Supersonics in Game 7 by a score of 105-99 to take home the championship trophy.

5. The Assassination Attempt on President Reagan: On March 30, 1981, John Hinckley Jr. attempted to assassinate President Ronald Reagan outside the Washington Hilton Hotel in Washington D.C. President Reagan was shot in the chest, and three others were injured, but all survived. The assassination attempt occurred on May 13.