(CNN) -- Fifty years ago Saturday, Berlin residents awoke in shock to a city divided overnight by barriers of simple concrete block walls and barbed wire, sternly guarded by communist East German soldiers ready to shoot to kill.
With Soviet backing, the communist regime in East Germany transformed that brick-mason's barrier into a wide swath replete with landmines, machine gun towers, anti-personnel devices, vehicle barriers and armed patrols -- the formidable and deadly Cold War military bulwark known as the "Berlin Wall."
The iconic graffiti-sprayed concrete barrier known the world over was merely its outer hull facing West Berlin.
Germany marked the anniversary of the birth of the Berlin Wall Saturday with a ceremony to remember at least 136 people who died trying to cross it and families the wall separated for decades, before it fell in 1989.
Residents of Berlin gathered quietly Saturday morning in the open air to hear German political leaders give speeches in celebration of democracy and listen to eye-witnesses re-live the sullen lessons and memories of a past that was less free, when Germany was divided into democratic West Germany and communist East German dictatorship -- ironically named the German Democratic Republic (GDR).
"The construction of the Wall hit us Berliners down to our bone marrow," said Berlin's senior mayor Klaus Wowereit in his speech to a crowd of thousands gathered in the open air. "Aghast, we could only just watch as the SED (communist) state cemented the division of our city. We were shocked and desperate."
Wowereit spoke in a narrow, symbolic street removed from the German capital's bustle. Bernauer Strasse was the scene of dramatic escapes on August 13, 1961, when whole families reacted to the new barrier and military presence by climbing out of the windows of buildings along the Wall and stepping onto the sidewalks -- which belonged to West Berlin -- and into freedom.
East Germany's communist regime built the wall to stop the flow of people leaving it behind. 2.7 million Germans fled the East for the West before the Wall went up, according to Germany's Press and Information Office, which published a special series on the history of the Wall.
"Many people tried to make it into the West at the last minute," Wowereit recalled. "The images shock us still today. They speak to the Berliners' innate need for freedom."
Today a dark, steel monument in the shape of an ominous, gray wall stands in Bernauer Strasse as a sad reminder of the division of Berlin, Germany and all of Europe into a democratic West and an Eastern block of communist regimes.
Germany's current chancellor Angela Merkel, who lived in East Germany in 1989, when the Wall fell, attended the services.
"I can remember exactly -- when I was seven years old -- I went with my grandmother from Pankow, East Berlin, to West Berlin a few days before the Wall was built," Merkel said in a video on the German government website.
Since she and her family were stuck behind the military barriers of the communist East, Merkel is happy the Wall is gone and felt an inner need to participate in Saturday's ceremony, she said.
"It was unfathomable for me as a child that suddenly Berlin was divided," Merkel said. "And I saw the grief of my parents and many friends on that Sunday, August 13, 1961. From then on I could no longer visit my grandmother in Hamburg."
The Berlin Wall stretched for 43.1 kilometers (nearly 27 miles) and contained 302 guard towers and 55,000 anti-personnel devices. East Germany militarized the entire border with the West, laying over one million land mines and deploying around 3,000 attack dogs, according to the German government. Around 1,000 people were killed while attempting to flee into the West.
Two months prior to the construction of the Wall, the East German head of state Walter Ulbricht assured West Berliners with a sentence that went down in modern German history as a notorious lie: "No one has the intention of constructing a wall!"