On 9 November 1989 East Germany's border restrictions collapsed and crowds breached the Berlin Wall that had divided the city since 1961, prefiguring German reunification the following year. The opening reconnected a metropolis that had been physically split, with its centre cut by the death strip. It triggered an extended period of reconstruction and redevelopment of the former no-man's-land and the wider former Eastern Bloc. Sites such as Potsdamer Platz became major redevelopment showcases through the 1990s.
The fall reopened the fundamental political questions of who plans the city and in whose interest, as state-socialist and market models met. The reunification of Berlin became a defining case study in stitching together a divided city and managing large-scale post-socialist urban transformation.