Berlin Hauptbahnhof fall of the Berlin Wall in 1989, city planners began work on a transport plan for reunified Berlin. One element of this became the "Pilzkonzept" (mushroom concept), in which a new north-south railway line intersecting the Stadtbahn was to be constructed. The name derived from the shape formed by the new line and existing lines, which vaguely resembles a mushroom. In June 1992 the federal government decided that the new station should be built on the site of Lehrter Bahnhof. While close to the centre of Berlin and government buildings, the area was still not heavily populated. The following year,
Berlin Customs Wall thus turning Berlin into a central transport hub for Prussia and the German Customs Union. With the rise of Berlin, new suburbs were built outside the Customs Wall, which increasingly became a hindrance to the continued development of the city. In 1860 the Customs Wall was removed and on 1 January 1861 Berlin amalgamated its suburbs resulting in a doubling of the city's population. The remaining walls were demolished for the most part between 1867 and 1870 - including most of the gates. Only some imposing gates were kept, the Brandenburg Gate being the only one to be rebuilt after