1. March 1, 1801: The District of Columbia's first mayor, Robert Brent, was inaugurated. Brent was appointed to the position by President John Adams and served until 1812.

2. March 1, 1872: Congress approved the creation of Yellowstone National Park, which included a small section of land in the District of Columbia. This section of land, known as "Rock Creek Park," was established in 1890 and is now a popular recreation area for residents and visitors.

3. March 1, 1919: The American Legion was founded in Paris, France by a group of U.S. military personnel who served in World War I. The organization's national headquarters are located in Washington, D.C.

4. March 1, 1954: The U.S. Army's School of the Americas was established in the District of Columbia. The school trained Latin American military officers in counter-insurgency tactics, but was eventually closed in 2001 due to controversy surrounding allegations of human rights abuses.

5. March 1, 1987: The District of Columbia's Metro system opened its first subway line, which included five stations between downtown Washington, D.C. and the suburbs of Maryland. The Metro now includes six lines and serves over 700,000 passengers each weekday.