1. On April 16, 1862, President Abraham Lincoln signed the Compensated Emancipation Act, which provided for the gradual freeing of enslaved people in the District of Columbia and compensated their owners for the loss of property. This act set a precedent for the eventual abolition of slavery throughout the United States.

2. In 1940, the Jefferson Memorial was dedicated in Washington, D.C. on April 16th, the 177th anniversary of Thomas Jefferson's birth. The memorial, located on the Tidal Basin, pays tribute to Jefferson's contributions to American history and serves as a popular tourist attraction.

3. On April 16, 1963, Martin Luther King Jr. wrote his famous "Letter from Birmingham Jail." The letter, written in response to criticism from white religious leaders who opposed his nonviolent civil rights demonstrations, became a seminal document of the civil rights movement and a call to action for social justice.

4. On April 16, 1972, the District of Columbia legalized abortion, becoming one of the first jurisdictions in the United States to do so. The law allowed women to obtain abortions in the first trimester of pregnancy and also permitted the procedure in cases of rape, incest, or the health of the mother.

5. In 1998, Washington, D.C. Mayor Marion Barry declared April 16th "Duke Ellington Day" in honor of the legendary jazz composer and pianist, who was born in the city in 1899. Ellington's music continues to influence jazz and popular music and his legacy is celebrated across the country.