Berlin on Saturday marks the 50th anniversary of the building of the Berlin Wall with a memorial service and a minute of silence in memory of those who died trying to cross it to flee to the West.
The Wall was born in the early hours of Sunday August 13, 1961, a day chosen by East German authorities as that most likely to catch people by surprise as they enjoyed a summer day off.
In a secret operation code-named "Rose", tens of thousands of East German soldiers and factory militiamen were called out to cut off the Soviet-occupied eastern sector from the western part of the city, occupied by US, British and French forces since the end of World War II.
The Wall, known in the East as the "anti-fascist protection wall", was set up to stop the exodus of East Germans who found it easy to cross into West Berlin and then fly on to the West rather than attempt to cross the inter-German border farther afield.
In 1961, more than 2.5 million of East Germany's 19 million inhabitants had already voted with their feet by going West and, with up to 3,000 leaving every day, communist authorities feared the mass flight would bleed the state dry.
Soldiers blocked off the streets, cut off rail links, and began building a wall of barbed wire and cemented paving stones which over the years, in Berlin, grew in height and complexity over 155 kilometres (96 miles).
Today much of the Wall had disappeared with only small portions, totalling about three kilometres, remaining.
"There is the accusation that too much of the Wall was torn down," Berlin Mayor Klaus Wowereit acknowledged last week.
"Tourists may see it that way. But back then we were just so happy that the Wall was gone and we couldn't wait for those excavators to come and do away with it, this thing that created such misery in this city, that divided families, that claimed so many victims and caused such suffering," he said.
"But perhaps more should have been left to really show the horror of the division," he added.
Sections of Wall still standing are now being restored and listed for historical preservation.
Concrete slabs along Bernauer Strasse, the site of dramatic escape attempts and now of the site of the main Wall memorial, will be repaired by year's end, according to memorial project director Guenter Schlusche.
"Most of the damage was done by the Wall woodpeckers between 1989 and 1991," Schlusche told AFP, using Berlin slang for the souvenir-hunters who chipped away at the Wall after the border opened on November 9, 1989.
German President Christian Wulff, Chancellor Angela Merkel, who grew up in the East, and Wowereit will attend a nationally televised service on Saturday morning at a chapel built where the Wall stood for 28 years.
And a number of groups, including one set up to commemorate "the victims of communist tyranny", have called for a minute of silence throughout the city at noon to remember those who died at the Wall.
Berlin's public transportation service said buses and trains would also stop to honour victims while electronic messages at stations would tell passengers the reason why.
At least 136 people are known to have died at the Wall. Historians suggest that the overall figure of those killed while fleeing from East to West stands at between 600 and 700.
For days, German newspapers and television channels have been marking the upcoming anniversary with interviews of people who tried to cross the Wall and programmes and documentaries about its history.
A number of exhibitions are also being staged, including one at the Friedrichstrasse station, the only point of crossing by subway during the division of the city.