In summer 1944 the Organisation Todt, also employing Soviet forced labourers else held captive at Blücherplatz, started driving five tunnels into the northern slope of the Kreuzberg from Kreuzbergstraße. The semi-completed tunnels were meant and used as air-raid shelters, while constructions continued until February 1945. In 1944 British bombing left behind a wake of devastation leading from one block north up the Großbeerenstraße, over the waterfall to the monument, damaging its socket structure, destroying villas on the northeastern Kreuzberg slope, and blocks of flats along Methfesselstraße, including Zuse's parental flat. The abandoned Schinkel-designed guard's house, though undestroyed, was demolished in the 1950s, its site is now used by a ball playing cage.