1. In 1843, the cornerstone of the Smithsonian Institution was laid in Washington D.C. by President John Tyler. The institution originally consisted of a museum, a library, and a research center for scholars, and has since become one of the world's largest museums and research complexes.

2. On July 5, 1865, William Booth established the Salvation Army in the United States in Washington D.C. The organization began as a Christian mission aimed at helping the poor and marginalized, and has since become a worldwide charitable organization.

3. In 1937, the U.S. Senate passed the National Housing Act, which established the Federal Housing Administration and the Federal National Mortgage Association (Fannie Mae). The act helped to stimulate the construction of new housing and stabilize the housing market during the Great Depression.

4. On July 5, 1971, the Washington D.C. City Council voted to officially change the name of "U Street NW" to "Dr. Martin Luther King Jr. Avenue." The street was once the hub of African American culture in the city, and renaming it was seen as a tribute to the civil rights leader's legacy.

5. In 1999, the D.C. United soccer team won their third Major League Soccer championship by defeating the Los Angeles Galaxy in the final match. The team has been one of the most successful in the league's history, winning four championships and eight conference titles since its inception in 1996.