The fall of the Berlin Wall on the 9th of November 1989 was a surprise for all Berliners. Thousands swarmed from East Berlin into the west. Only two days later, the Jannowitzbruecke U-Bahn station was opened as a provisional border crossing point. A short time later work began to reconnect all sorts of networks that had been divided for decades. However the old water and electrical lines in the border areas were completely unusable and had to be redone. In contrast, all 52 barriers in sewage system had been removed by the middle of 1991. Jackhammers were used to tear out the iron railroad tracks and pipes that had separated east and west. Similarly, the “ghost stations” were brought back to life exceptionally quickly. As the border controls done away with on the 1st of July 1990, almost all of U and S-Bahn stations in the east were back in service.
After the underground infrastructure of both sides of the city had been reconnected, and the holes in the transportation system had been for the most part filled, a new building boom began in Berlin. Half of the investment into Europe’s largest construction site at Potsdamer Platz went into the underground. Before construction could begin, metres of “cultural debris” had to be removed. Yet such things were not found only at Potsdamer Platz, throughout the city, remnants of better days were to be found – along with relicts of death and destruction from the end of the war. Parts of shells and weapons and even half of a “Stalin organ” were discovered, and similar items can still be found today. As a construction worker found a soldiers skull – still wearing a helmet – shock prevailed. The majority of the excavation work had to be carried out by armoured diggers and often the munitions recovery dept. of the police had to be called to deal with unexploded bombs.
Time and again bunkers were rediscovered. Already in 1990, during the preparations for the Roger Waters concert “The Wall”, which involved the clearing of munitions, the bunker for the Chauffeurs of the SS was discovered. The murals on the walls of the bunker that glorified Nazi ideology attracted the attention of the world’s press. In 1992 the reinforced concrete ceiling of the “Adlon Bunker” had to be cut away to make room for the reconstruction of the historical fountains on Pariser Platz. The Deutsche Genossenschaftsbank (German credit union) ran into problems when they hit the forgotten “Speer Bunker”. Missed during the site surveys, the removal of the bunker led to long delays in construction.
One year later during the clearing work for the offices of the federal state representatives and the Holocaust memorial the “Goebbels Bunker” was found. The construction workers, with no knowledge of the bunker, drilled through the 1.8 metre-thick reinforced concrete ceiling rather than using the entrance nearby. The climax of these rediscoveries involved the accidental uncovering of a corner of Hitler’s bunker in October 1999, which led to a debate about how to deal with the site.
It wasn’t the big investors that were the first after reunification to be active in the underground. As the architects were still sitting around their drawing-boards, a club scene was developing in Berlin’s underground that gained notoriety far beyond the borders of the city. In March 1991, in the remains of the Wertheim complex on Leipziger Strasse – once the largest department store in Europe, “Tresor” opened its doors. Of the splendour of the twenties and thirties, only the underground safe remained, which lent the club its special ambience. Other sauces were also rediscovered. In the toilet rooms under Leipziger Platz the club “WMF” resided for one year, as did the club “E-Werk” in the old Bewag substation on Wilhelmstrasse. In the cellars of derelict buildings in the area, further such temporary establishments were to be found, for example a Caipirinha bar, whose dimly lit entrance could only be found by those in the know. Yet little remains of this scene today. Along with the first building cranes, the scene moved into other parts of the city. The last survivor, “Tresor”, was forced to close its doors on the 16th of April 2005.
On the 29th of October, the ground-breaking of the “debis-complex” was celebrated at Potsdamer Platz. For this project of the major investors, huge constructions pits were dug, many hectors in size, some up to 20 metres deep. The sides were secured with giant reinforced concrete walls that were lowered into up to 25 metres into the ground. These walls, which secured the borders of the site, had to be anchored in the ground to prevent them from tipping over, before the actual digging could begin.
The ground water that was already reached after three metres turned the entire area into a group of lakes. Not only were dredges used, also divers were involved in sealing the floor of the excavation pit, which was in turn anchored in the underground. This served to hinder a worst case scenario at the construction site – when the water was pumped out, the pressure of the ground water underneath could have forced the entire fundament upwards. The fundaments were considered secure, only when the buildings were completed to the point that the pressure pushing downwards was equal to the pressure from below.
2.8 million tons of earth had to be removed from the 68,000m² “debis” site alone. For the up to four underground levels, 2,500m² of concrete were used on a daily basis. The spectacular building site in the heart of the city developed quickly into one of Berlin’s most important tourist attractions. Over 50 building cranes were in use. Between 1997 and 1998 over 4,000 workers were simultaneously working on 19 buildings, 10 streets, an underground regional train station, an underground highway, a parking garage on Koethener Strasse, and the 12,000m² of man-made lakes. 2,500 of the planned 4,000 parking places were in the underground garage. Despite the scale of the plans, the “debis complex” was opened after only four years, on the 2nd of October 1998, followed by the 1.5 billion deutschmark “Sony complex” on the 14th of June 2000.