1. In 1802, the United States Congress passed the Organic Act, which officially established the District of Columbia as a federal district. The act provided for the creation of a municipal government and the appointment of a mayor and other officials to govern the new district.

2. On May 3, 1862, during the American Civil War, Union troops under the command of General Irvin McDowell defeated Confederate forces at the Battle of Williamsburg. The battle was part of the Peninsula Campaign, a Union effort to capture Richmond, Virginia, the capital of the Confederacy.

3. In 1901, the McMillan Plan for the development of Washington, D.C., was unveiled. The plan called for the creation of a system of parks and open spaces, the renovation of monumental public buildings, and the construction of new government buildings and public amenities.

4. On May 3, 1971, the Washington Metropolitan Area Transit Authority (WMATA) began operating the first segment of the Washington Metro subway system. The initial segment, which included five stations, served the Red Line between Rhode Island Avenue and Farragut North.

5. In 2015, Washington, D.C., became the first jurisdiction in the United States to legalize marijuana for recreational use without a voter initiative. The law, which took effect on February 26, 2015, allowed adults over the age of 21 to possess up to two ounces of marijuana and grow up to six plants at home for personal use.