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 Wall Day. On 9 November 2009, Berlin celebrated the 20th Anniversary of the Fall of the Berlin Wall with a "Festival of Freedom" with dignitaries from around the world in attendance for an evening celebration around the Brandenburg Gate. A high point was when over 1,000 colourfully designed foam domino tiles, each over tall, that were stacked along the former route of the Wall in the city center were toppled in stages, converging in front of the Brandenburg Gate. A Berlin Twitter Wall was set up to allow Twitter users to post messages commemorating the 20th anniversary. The Chinese government quickly