The Copenhagen Metro is a light rapid transit system in Copenhagen, Denmark, serving the municipalities of Copenhagen, Frederiksberg, and Tårnby. The original 20.4-kilometre system opened in OctoโฆThe Copenhagen Metro is a light rapid transit system in Copenhagen, Denmark, serving the municipalities of Copenhagen, Frederiksberg, and Tårnby. The original 20.4-kilometre system opened in October 2002, serving nine stations on two lines: M1 and M2. In 2003 and 2007, the Metro was extended to Vanløse and Copenhagen Airport respectively, adding an additional six plus five stations to the network. In 2019, seventeen stations on a wholly underground circle line, the M3, was added bringing the number of stations to 37.