Washington, D.C. District of Columbia is the capital of the United States, founded on July 16, 1790.
The city is located on the north bank of the Potomac River and is bordered by the states of Virginia to the southwest and Maryland to the other sides. The District has a resident population of 599,657; because of commuters from the surrounding suburbs, its population rises to over one million during the workweek. (From Wiki)
Photos taken from a very short trip (less than a day) in 2008,