Fifty years ago this morning, Berliners awoke to the sound of pneumatic drills digging up the road in front of the city's famous Brandenburg Gate.
They watched incredulously as squads of labourers, guarded by armed Communist militiamen, unrolled huge reels of barbed wire and pinned them to the tarmac with giant staple guns.
The barrier erected on 13 August 1961 was the beginning of that infamous structure which even today – nearly 22 years after its fall – remains one of the Cold War's most potent symbols: the Berlin Wall. At noon today, Berlin will come to a standstill. Chancellor Angela Merkel and German President Christian Wulff will be among 100 dignitaries who will attend a memorial ceremony close to the site of the former Wall to remember the fateful day of its building half a century ago.
Buses and tubes will stop running and many Berliners, especially the thousands whose lives were forever changed by the Wall, will stand in silence for a minute. The ceremony will end with the reading out of the names of all the 136 East Germans who were shot dead by border guards or otherwise perished at the Wall while trying to escape the tyranny of Communist rule. Many more died while trying to escape over the heavily mined and fenced border between the two Germanys.
The Berlin Wall was a desperate measure taken by the rulers of "the first workers' and peasant state on German soil" to stem the human haemorrhage it was suffering in the months leading up to 13 August 1961. Until then, tens of thousand of East Germans were voting against the system with their feet and staging a mass exodus to the West.
By the summer of 1961, the communist leadership was panic-stricken: not only had vast numbers of doctors, teachers and engineers left the country. Factories were losing staff and there were fears that there would not be enough farm workers to bring in the harvest.
The Wall was the leadership's answer to the problem. But barriers and barbed wire were not enough. The so-called "anti-fascist protection barrier" had to be "defended" by Kalashnikov-toting border guards to render it effective. The death toll began nine days later when Ida Siekmann, a 59-year-old East Berliner, died from the injuries sustained after she tried to escape to West Berlin by jumping out of the window of her apartment, which stood directly on the border.
The first person to be shot dead, two days later, was Günter Litfin, a young Berliner who had been visiting his mother in the east before the Wall suddenly went up. He couldn't believe that he could never return to the flat he had just rented in the West. He was shot in the back of the head by border guards while trying to escape across the Spree River that flows through the city centre. Hundreds of stunned West Berliners lined the river bank to watch firemen retrieve his dead body.
The Wall claimed what was to be almost its last victim in February 1989, just eight months before it fell. 21-year-old Chris Gueffroy was shot in the heart by an East German border guard as he tried to escape across the Wall next to two allotment gardens called "Harmony" and "Carefree". He had mistakenly assumed that the regime had suspended its order to shoot escapers. A month later the East Berliner Winfried Freudenberg plunged to his death in West Berlin from the home-made hot air balloon he had built to escape in.
For thousands of Berliners, the Wall is still something they would rather forget. The remaining traces of it have all but disappeared from the reunited capital. Its politicians have yet to decide how best to keep its memory alive for posterity.