1. In 1861, the United States Congress passed a law that abolished slavery in the District of Columbia, a full two years before the Emancipation Proclamation was issued by President Abraham Lincoln.

2. On June 29, 1925, the iconic theater venue The Howard Theatre opened its doors in Washington, D.C. The venue became a hub of African-American entertainment and music during the height of segregation, hosting legendary performers like Duke Ellington, Ella Fitzgerald, Billie Holiday, and Marvin Gaye.

3. In 1941, President Franklin D. Roosevelt declared the District of Columbia to be a "closed city" and prohibited photography in certain areas due to concerns about national security during World War II.

4. June 29, 2008, saw the opening of the Smithsonian's National Museum of African American History and Culture in Washington, D.C., marking the culmination of decades of work by activists and scholars to establish a national museum dedicated to African-American history and culture.

5. In 2015, the Supreme Court of the United States ruled in the landmark case Obergefell v. Hodges that same-sex couples had the constitutional right to marry, overturning bans on same-sex marriage in the District of Columbia and other states across the country. The decision was celebrated by LGBTQ activists and supporters in Washington, D.C. and around the world.