Following years of delay, cost overruns and heated political wrangling, the U.S. Capitol Visitors Center in Washington, D.C., opened its doors to the public on Dec. 2. The $621-million underground facility includes 580,000 sq ft of space spanning three levels, representing the largest project in the history of the U.S. Capitol complex and its first using an outside construction manager. The facility, designed by RTKL, Baltimore, is the new entry for building visitors and improves security screening. The project, led by CM Gilbane Building Co., Providence, R.I., broke ground in 2002 with an estimated $265-million budget. Costs then escalated due to security-mandated and congressionally requested design changes and other disputes.