The United States Department of Transportation building is a two million square-feet office building that is home to the Secretary of the DOT and approximately 7,000 employees. Comprised of two office building and an underground connecting concourse, the building opened in 2007 and further defined the Capitol Riverfront neighborhood as an office submarket. The historic 3rd Street, SE right-of-way was preserved as a connection to Yards Park. The site previously housed temporary office and manufacturing buildings for the Washington Navy Yard. The building complex was designed by noted architect Michael Graves in the Post-Modern style. The building site contains a transportation history walking tour and numerous artifacts from the transportation industry.