|Harald Jäger disobeyed orders and opened the border gates on November 9 [Penny Bradfield]
Many events, large and small, in the East and the West, helped to bring the Cold War to a peaceful end.
But it is the events of November 9, 1989, that the world remembers.
The 154km of reinforced concrete and barbed wire, enclosing half a city, came to symbolise a government that could not trust its own people.
For the second time in the 20th century Berlin hosted the last battle in a global war. But this time, instead of laying in ruins, it stood unscathed. Rather than clearing rubble and building from scratch, Germany became a whole country again in less than a year.
Al Jazeera spoke to people who are witnesses to that period, their lives shaped by the political divide that dominated the second half of the 20th century. In turn, they helped to shape those events that the world celebrates on Monday, November 9, 2009.
If history is just the sum of countless individual decisions, then Harald Jäger's contribution is this: When Germany marks the 20th anniversary of the fall of the Berlin Wall on Monday, it will be a celebration, not a memorial day.
If there is mourning, it will be for the people who died and suffered before November 9, 1989, including as many as 200 who were shot dead trying to escape over the wall. But that night, despite the panic, the upheaval and the paralysis in military command, not a shot was fired.
By then the fall of the wall was inevitable. But Jäger, probably more than any other person, made sure it happened without bloodshed.
After 28 years spent loyally maintaining the integrity of the wall that kept East Germany's 16 million citizens hemmed in, and fervently believing in the ideology he was protecting, Jäger was the man who broke ranks. That night, he disobeyed orders and opened his gate, letting thousands of jubilant East Berliners through to the West.
The Bornholmerstrasse checkpoint, where he was the Stasi officer in charge, became the first to open at 11:30pm. It broke the dam and, one by one, other checkpoints across the city opened.
"It was the best night and the worst night," Jäger, 66, recalls. "The worst part was that I felt completely abandoned by my superiors. I was left in the lurch.
"I realised that the people I was taking orders [from] for so many years just did not know how to react. They could not cope with something like this.
"My life's philosophy was shattered. I knew that after this night, I'd be starting from zero.
"The best part was that we [the border guards] were drawn into the joy. The people - our people - embraced us."
Like millions of Berliners, Jäger watched the 'shambolic' press conference at which East German official Günther Schabowski prematurely announced that the East German borders were open "immediately, without delay".
Jäger was at the time eating a sandwich at the border guards' cafeteria. He swore aloud. Nobody knew a thing about it.
|Two border guards watch each other from opposite sides of the wall [GALLO/GETTY]
"We thought, if there's confusion in here, imagine what the people are thinking out there."
By the time he reached his station at Bornholmerstrasse, people had already begun to amass. For three-and-a-half hours he faced them, letting only the most boisterous at the front pass through the checkpoint, in the hope of calming the crowd.
Meanwhile he was making frantic calls to his superiors and being told not to open the boom gate. "What am I supposed to do? Shoot them?" he asked at one point in exasperation.
It was never a consideration for him, he says today.
"Shooting was not an option. But neither was doing nothing. Doing nothing would have been the same as shooting because it would have led to a riot."
Worried about the press of the crowds, the danger to those at the front and to his own officers if panic broke out, and hopelessly disillusioned with his superiors, Jäger gave the order for the boom gate to be lifted. He did it to avoid catastrophic harm to the people he considered his own.
"In a crowd that big, panic would have been deadly. I thought about the consequences - about what it would mean. And then I did what I had to do."
Until that night, he had thought the growing civil unrest in the GDR, Moscow's glasnost and perestroika, and the emergence of more moderate regimes in Hungary and Czechoslovakia would lead to a compromise, a softened form of Communism in East Germany, not its total collapse.
But as a fellow officer mumbled to him that night: "That's that, then."
"That's what?" Jäger asked.
"That's it for the GDR," the colleague replied.
The rest, as they say, is history.
For Jäger, it has been a winding road. Within the dying embers of the GDR, the government made a half-hearted attempt to prosecute him for disobeying orders, but it went nowhere.
The father of three spent some time unemployed after the wall fell, then had various jobs, but says his Stasi history made him a "hot potato". It took time, but he came to realise the true malignancy of the regime he defended.
"If I have regrets, it's that I did not realise this sooner, that it took me that long to realise how wrong the philosophy was."
Looking back, he feels relieved, rather than proud that "not a single GDR citizen got a scratch".
"The heroes were the people standing in front of me at the gate. They did not know what was going to happen that night. They did not know if they were going to be shot."
One of those heroes was Siegbert Schefke, a young journalist who was the first through Borholmerstrasse that night. Three weeks ago, the two men came face to face for the first time since that night in 1989 for a Swiss television programme.
Jäger apologised - not for November 9, but for everything that came before it.