On 27 September 1921 the borough assembly of the VIth borough of Berlin, established on 1 October 1920 and provisionally named Hallesches Tor, decided to rename the borough after the hill into Kreuzberg. In 1926 the Kreuzberg underground station opened for traffic, renamed into Flughafen (i.e. airport) in 1937 (Platz der Luftbrücke since 1975).