Introduction to the Capitol Building: Washington is the political center of the United States. The White House, Congress, the U.S. Supreme Court and most government agencies are located here. The Capitol Building is built on the highest point in the city known as "Capitol Hill" and is a symbol of Washington. This milky-white building has a domed main building and interconnected east and west wings. The U.S. House of Representatives and the Senate are housed in the Capitol Building.