Washington DC is the capital city of the United States, located on the Potomac River. It is known for its many parks, wide streets, and impressive buildings like the White House and Capitol building. The White House is the official residence of the President and is situated at 1600 Pennsylvania Avenue, containing rooms like the East Room, Green Room, and Blue Room used for receptions. Other landmarks include memorials to presidents as well as the Library of Congress and National Gallery of Art.