On Saturday 12 Aug. 61, the leaders of the GDR attended a garden party at a government guesthouse in Döllnsee. There, Ulbricht signed the order to close the border with immediate effect.
At midnight, the police and East German army began to close the border. By Sunday morning, on August 13, the border with West Berlin was closed. East German workers, under the guard of the troops of the NVA and KdA tore up streets and installed barbed wire and fences along the 156 Kms surrounding the 3 western sectors, and the 43 Kms that divided West and East Berlin.
The barrier was built slightly inside the Eastern German territory to ensure that it did not encroach on West Berlin, occasionally some distance from the legal border, such at Potsdamer Bahnhof known now as the Potsdamer Platz modern complex. Later, the initial barrier materialized into the actual proper concrete Wall. The first segments were laid on the 17th of August.
Western Berliners soon named it “Schandmauer” (“Wall of Shame”), term that would be relayed by Western medias and politicians. For the Eastern authorities, the construction of an “Anti-Facist Rampart” was justified to put a stop to the emigration of Eastern Berliners (up to 3 millions since the end of the war, nearly a fifth of the GDR population), especially the younger workforce and the most educated “brains”, and discourage the exception of the quarter million of Grenzgängers.
Although, travels of Germans from the GDR had been limited since 1956, the Wall, if not torn in the Fall of 1989, would have been 55 years old today.