Washington Union Station, known locally as Union Station, is a major train station, transportation hub, and leisure destination in Washington, D.C. Designed by Daniel Burnham and opened in 1907, it is Amtrak's headquarters, the railroad's second-busiest station, and North America's 10th-busiest railroad station. The station is the southern terminus of the Northeast Corridor, an electrified rail line extending north through major cities including Baltimore, Philadelphia, New York City, and Boston, and the busiest passenger rail line in the nation. In 2015, it served just under five million passengers.An intermodal facility, Union Station also serves MARC and VRE commuter rail services, the Washington Metro, the DC Streetcar, intercity bus lines, and local Metrobus buses. It carries the IATA airport code of ZWU.At the height of its traffic, during World War II, as many as 200,000 passengers passed through the station in a single day. In 1988, a headhouse wing was added and the original station renovated for use as a shopping mall. As of 2014, Union Station was one of the busiest rail facilities and shopping destinations in the United States, visited by over 40 million people a year. However, the COVID-19 pandemic and other factors caused a sharp decline in retail and dining; by late 2022, more than half its commercial space was vacant, but Amtrak is attempting to regain control of the station and plans a major renovation and expansion.