US Capitol, Washington DC, USA - stock photo

The United States Capitol, often called the Capitol Building or Capitol Hill, is the home of the United States Congress, and the seat of the legislative branch of the U.S. federal government. It sits atop Capitol Hill at the eastern end of the National Mall in Washington, D.C. Though not at the geographic center of the Federal District, the Capitol forms the origin point for the Districts street-numbering system and the Districts four quadrants. The original building was completed in 1800 and was subsequently expanded, particularly with the addition of the massive dome. Like the principal buildings of the executive and judicial branches, the Capitol is built in a distinctive neoclassical style and has a white exterior.