Washington DC, also known as the District of Columbia, is our nation's capital and one of its largest cities. It was created in 1790 with the residence act, approving of a capital district. Therefore Washington DC does not belong to any US State. Within Washington D.C. are the white house, congress, many national memorials, the pentagon, many national museums, and a plethora of other monuments and structures. It is a great place to visit. These are free public domain photos from our nation's capital.