Copenhagen Metro is a rapid transit system serving Copenhagen, Frederiksberg and Tårnby in Denmark. The 20.5-kilometer (12.7 mi) system opened between 2002 and 2007, and has two lines, M1 and M2. The driverless light metro supplements the larger S-train rapid transit system, and is integrated with DSB local trains and Movia buses. Through the city centre and west to Frederiksberg, M1 and M2 share a common line. To the south-east, the system serves Amager, with the 13.7-kilometer (8.5 mi) M1 running though the new neighborhood of Ørestad, and the 14.2-kilometer (8.8 mi) M2 serving the eastern neighborhoods and Copenhagen Airport. The metro has 22 stations, of which 9 are underground. In 2009, the metro carried 50 million passengers.
Planning of the metro started in 1992 as part of the redevelopment plans for Ørestad. A tramway and light rail were considered, but discarded in the process. Construction started in 1996, and stage 1, from Nørreport to Vestamager and Lergravsparken, opened in 2002. Stage 2, from Nørreport to Vanløse, opened in 2003, followed by stage 3, from Lergravsparken to Lufthavnen, in 2007. Construction of the City Circle Line is underway, and is scheduled to open in 2018. It will form a circle around the city center, be entirely underground and not share any track with M1 and M2. A further expansion towards Brønshøj is being considered. On Jan 7, 2011 the new project called Cityringen started with the signature by Metroselskabet of new contracts, with Ansaldo Breda and Ansaldo Sts (Finmeccanica Group) for the supply of trains and control systems and with an Italian joint-venture led by Salin Construttori (about 60%) and Tecnimont (about 40%) with Seli as third partner for the construction part.