1. On June 6, 1968, the assassination of Senator Robert F. Kennedy at the Ambassador Hotel in Los Angeles, California shocked the nation and especially the District of Columbia. His memorial service was held the next day at St. Matthews Cathedral in DC.

2. In 1874, the US Patent Office opened the new patent building in the city, which was called "the temple of invention" at the time. It was designed to house the ever-growing collection of patents and inventions, and was one of the largest buildings in the country at the time.

3. The city of Washington DC was officially recognized as the capital of the United States on December 24, 1799. However, it wasn't until June 6, 1800 that President John Adams moved into the newly-completed White House.

4. The Lincoln Memorial was dedicated on May 30, 1922, but it wasn't until June 6 of that year that the public was allowed to view the statue of Abraham Lincoln up close. The statue itself is 19 feet tall and weighs over 175 tons.

5. On June 6, 1963, President John F. Kennedy gave a speech at American University in DC that was called "A Strategy of Peace". In it, he outlined his vision for a world without nuclear weapons, and stressed the importance of diplomacy and cooperation between nations instead of relying on military deterrence.