1. The District of Columbia Organic Act was signed into law on March 22, 1871. This act established a new form of government for the District of Columbia, with an appointed governor and council instead of an elected mayor and council.

2. On March 22, 1915, the U.S. Navy opened its first submarine base in the District of Columbia. The base, located in Anacostia, served as the primary training facility for submarine crews during World War I.

3. On March 22, 1967, a group of poets staged a protest outside the Pentagon in the District of Columbia. The poets, including Allen Ginsberg and Amiri Baraka, read from their work and demanded an end to the Vietnam War.

4. The National Zoo in the District of Columbia welcomed its first giant pandas on March 22, 1972. Hsing-Hsing and Ling-Ling were gifts from China and quickly became popular attractions at the zoo.

5. On March 22, 1991, the District of Columbia hosted its first-ever St. Patrick's Day parade. The parade, which has become an annual tradition, features marching bands, floats, and festive attire in celebration of Irish heritage.