U.S. Capitol Visitor Center

The United States Capitol Visitor Center is a large underground addition to the United States Capitol complex which serves as a gathering point for up to 4,000 tourists and an expansion space for the U.S. Congress. It is located below the East Front of the Capitol and its plaza, between the Capitol building and 1st Street East. The complex contains 580,000 square feet of space below ground on three floors. The overall project's budget was $621 million.

The CVC has space for use by the Congress, including multiple new meeting and conference rooms. On the House side, there is a large room which will most likely be used by a committee. The new Congressional Auditorium, a 450-seat theater, is available for use by members of Congress or for either House of Congress should their respective chamber be unavailable.

Source: Wikipedia