1. On January 3, 1863, President Abraham Lincoln signed the Emancipation Proclamation, which declared all slaves in Confederate territory to be "forever free." While the document did not immediately free all slaves in the country, it was a crucial step towards ending slavery in the United States.

2. January 3, 1924, marked the opening of the Jefferson Memorial Book Room, which houses a collection of books, manuscripts, and other materials related to the life and legacy of Thomas Jefferson. The book room remains a popular attraction for visitors to the monument today.

3. In 1967, the American University in Washington D.C. became the first university in the United States to offer a Ph.D. program in computer science. Today, the school is known for its strong programs in both computer science and cybersecurity.

4. January 3, 1983, saw the opening of the Air and Space Museum Annex at Washington Dulles International Airport. The museum, which is now known as the Steven F. Udvar-Hazy Center, exhibits an extensive collection of historic aircraft and spacecraft, including the Space Shuttle Discovery.

5. On January 3, 2003, the Washington, D.C. City Council approved a measure legalizing same-sex marriage in the district. This made Washington D.C. one of the first places in the country to allow same-sex couples to marry, and helped to pave the way for marriage equality across the United States.