The United States Capitol Visitor Center (CVC) is a large underground addition to the United States Capitol

United States Capitol

The United States Capitol is the meeting place of the United States Congress, the legislature of the federal government of the United States. Located in Washington, D.C., it sits atop Capitol Hill at the eastern end of the National Mall...

 complex which serves as a gathering point for up to 4,000 tourists and an expansion space for the US Congress

United States Congress

The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....

. It is located below the East Front of the Capitol and its plaza, between the Capitol building and 1st Street East. The complex contains 580000 square feet (53,883.8 m²) of space below ground on three floors.