1. In 1830, the Chesapeake and Ohio Canal Company was incorporated in Washington, D.C. This enabled the construction of a canal that would connect the Chesapeake Bay to the Ohio River, and played a vital role in the expansion of trade and transportation within the region.

2. On May 28, 1861, the United States Patent Office caught fire and burned to the ground. Approximately 87,000 patents were lost as a result of the fire, and it took the government over a decade to reconstruct the documents that were lost.

3. In 1928, the construction of the Lincoln Memorial was completed in Washington, D.C. This iconic landmark was built to honor the 16th President of the United States, Abraham Lincoln, and is considered one of the most impressive memorials in the country.

4. On May 28, 1959, the U.S. Supreme Court issued a ruling in NAACP v. Alabama that affirmed the right of the NAACP to keep their membership lists confidential. This was a significant victory for civil rights advocates, as it prevented individuals from being persecuted for their involvement in the organization.

5. In 2009, President Barack Obama delivered a speech at the National Archives in Washington, D.C. outlining his commitment to national security and civil liberties. This speech marked a pivotal moment in the Obama administration's approach to counter-terrorism and surveillance policies.