Launched in 2013 the TBMs faced lime, gravel, sand and stone along with major challenges like passing below historic buildings, and difficult geological conditions such as the valley next to City Hall. Tunnels have an id of 4.9m.

Prime minister Lars Løkke Rasmussen made a brief speech at the milestone celebration: "I have followed the metro construction closely. From my apartment in Nyhavn, I have been able to hear it. When I am walking the dog, we often walk past Kongens Nytorv, and from my office at Christiansborg, I can almost wave to the crane operator. It will be a huge advantage to get some traffic away from congestion and under ground.”

The Cityringen will open in July 2019, connecting Østerbro with Nørrebro, Frederiksberg, Vesterbro and Downtown. The line will have 17 new stations in central Copenhagen.

The contractor responsible for civil construction work is the Copenhagen Metro Team JV comprising Salini Costruttori, Tecnimont and Seli. Cowi, Arup and Systra handled vibration analysis as well as all other design and engineering works.