Within two or three days, though, reality hit. “You couldn’t close the wall again,” recalled Mr. Ebert, who helped to organize celebrations here this weekend for the anniversary of the wall’s demise. “Very quickly it was normal.”
Twenty-five years later, it is so normal that many residents of this increasingly cosmopolitan European capital can hardly relate to life in the heavily militarized, divided city of the days before Nov. 9, 1989. Moritz van Dülmen, director of Kulturprojekte Berlin, the organizer of the anniversary event, estimates that roughly half of today’s residents never had direct experiences with the 96-mile barrier.
Now, slick, modern buildings trace the wall’s footprint. A section of what was known as “death strip” — a sliver of heavily mined land lined by watch towers — is now a park known for its Sunday flea market and open-air karaoke.
While dozens of institutes, museums and governmental offices are dedicated to remembering Germany’s complicated and painful history, their focus is largely on the crimes and victims of Hitler’s Third Reich. What has surprised Mr. Ebert and others is the speed with which the Berlin Wall’s history, albeit relatively brief, has been forgotten, and how quickly people have left it in the past.
“In the beginning, it was a real fight to get people to understand how important it is, to remember how horrible it really was in the German Democratic Republic,” said Mr. Ebert, who runs an archive devoted to materials from the former East German opposition. “What happened around the wall is not normal.”
To remind Berliners and others of the night when the Communist authorities effectively made it possible for East Germans to travel, Berlin organizers lined more than eight miles of the inner-city border with an installation of 8,000 illuminated balloons — biodegradable for this environmentally conscious country.
The balloons, each bearing a message of hope or congratulations, were released Sunday to the cheers of thousands.
The project was the visual highlight of a multitude of events and gestures celebrating the anniversary, including guided tours, the unveiling of a memorial to the tragedies wrought by the wall and a debate with Mikhail S. Gorbachev, the former Soviet leader, now 83, whose shift toward democracy helped make the wall’s collapse possible.
Other events on Sunday included a speech by Chancellor Angela Merkel, church services and concerts featuring works by Bach and Beethoven.
The “Lichtgrenze,” or Border of Light, installation was meant to evoke the brutal division of the past. At the same time, its use of modern materials and techniques symbolized how much the city and the world around it have changed in a quarter-century.
Many of the balloons’ messages honored the role played by tens of thousands of East Germans in creating the conditions for the wall to be torn down.
But while East German activists trying to break free of Communist repression were forced to smuggle messages across the border to Western reporters and spread news of protests through hand-printed pamphlets or word of mouth, organizers of the installation were able to reach people across the world through social media, now a principal organizing tool in political movements.
“We wanted people to be able to participate, for it effectively to come from the people, as it did back then,” said Mr. van Dülmen, who organized the event with Mr. Ebert of the Robert Havemann Gesellschaft archives. “Back then it was the people who freed themselves.”
Against the background of a changing Soviet Union, East Germans had been gathering throughout the fall of 1989, first in Leipzig and then in Berlin, in ever-larger numbers, staging peaceful demonstrations and demanding the right of representation.
On the night of Nov. 9, 1989, officials suddenly announced that East Germans would be allowed to travel, and crowds turned out by the tens of thousands demanding the opening of a checkpoint at Berlin’s Bornholmer Street. The border guards let them through, unhindered.
In the heady months that followed, Berliners rushed in to remove most of the concrete slabs of the structure that had divided their city for nearly 28 years; 138 people died at the barrier over the years. Vestiges of the wall remain, scattered through the city and in a central memorial on Bernauer Street. But little by little, the wall has faded from sight and memory as new apartments and buildings fill the gaps.
In the past few years, a city that its mayor, Klaus Wowereit, described in 2004 as “poor, but sexy,” has grown into its role as the seat of government of Europe’s largest economy, a center of vibrant technology and creative sectors. More than 45,000 new jobs were created last year, drawing nearly the same number of new residents to this city of 3.5 million.
Because Berlin has so many newcomers and residents born since unification, organizers said it was important to provide a vivid reminder of what it meant to live in a city and country where families were kept apart under threat of death.
“So many things have changed,” said Christopher Bauder, 41, a lighting designer based in Berlin, who conceived the balloon installation with his brother, Marc. “There’s buildings where the wall was. The scars are slowly growing over, but I think it’s good from time to time to tear it open just a little bit and take a peek at what it might have been like to live in this city back then.”
With the passage of time, some have been vigilant about the need to save surviving pieces of the wall. When city officials threatened last year to dismantle the East Side Gallery, a 70-foot section that was the longest remaining stretch, to make way for a luxury apartment complex, protesters came out in droves.
Still, said Mr. Bauder, “It’s really hard sometimes to find where it actually goes.” The installation will, at least temporarily, jar memories.
“The wall was heavy, was big, was dark,” Mr. Bauder said. “We wanted to contrast it with something ephemeral, light and potentially beautiful.”