Washington DC is the heartbeat of the entire United States nation. Attractions here aren't hard to come by, it's getting it all into one trip that's the problem. Stop by the National Mall and see the Declaration of Independence at the National Archives. Sit at the steps of the Lincoln Memorial. Walk along the Vietnam Veterans Memorial. Enjoy all the US Capitol has to offer.
I just got home from visiting D.C. and was wondering what the distance is between the capital and the Lincoln Memorial? Does anyone know? because I walked it.