The National Mall is the must-see destination in Washington DC. This world-famous landscaped park is home to some of the most historically significant buildings in America. One of the highlights of your tour will be The Capitol. It was completed in 1800 and is the seat of Congress, but nowadays much of the building is also a museum. The Library of Congress is part of the Capitol. It houses 40 million books translated into 470 languages, as well as films, maps, photos, documents and sheet music. The White House is also a museum that functions simultaneously as the home of the head of state. It has been occupied by every U.S. president since John Adams. But what lurks behind those walls is fascinating.