BERLIN, July 17, 2010: Just over 20 years ago, this part of Berlin echoed to the wail of alarm sirens and the howls of attack dogs guarding the Wall that split the German capital, the uneasy front line in the Cold War.

Now, the "Wall Park", a strip once divided by the hated barrier, hums to the sound of people butchering Michael Jackson and Britney Spears hits as thousands of Berliners turn up here every Sunday to enjoy a huge open-air karaoke show.

One spring Sunday in 2009, Joe Hatchiban, a 36-year-old Irish courier living in Berlin, fired up his laptop and a microphone and held an impromptu karaoke competition with just a scattering of people sitting in the park.

"I live here around the corner so one Sunday I just came round here and set up the sound system. I just started singing a few songs with just five or six people," he told AFP.

The five or six participants on that first Sunday quickly became hundreds, then thousands. And more than a year later, what was impromptu has become an institution, a "must-do" event among Berlin's young bohemians.

One recent Sunday, two skinny teenage girls grip their microphones tightly and fight -- unsuccessfully -- to make their rendition of "YMCA" heard above the enthusiastic crowd.

"It's fun to stay at the YMCA," screams the colourful crowd, the women in flowery mini-skirts, the men with their oiled torsos swaying to the Village People dance.

Others make a fist of the "Macarena", "I Will Survive", "It's Raining Men", "Like a Virgin" and the Cold War anthem "Wind of Change" -- "all the karaoke classics," said Hatchiban.

The scene could hardly provide more of a contrast to the seven-hectare (17-acre) no-man's-land that from 1961 to 1989 separated the West Berlin district of Wedding from Prenzlauer Berg, in the East.

The barbed wire and watchtowers have been replaced by barbecues and trendy buggies, the only remnant of the Wall that once carved the city in two is a graffiti-strewn hind section.

And, proof that capitalism is alive and well in the former communist zone, the open-mike extravaganza now attracts people selling beers and soft drinks to lubricate throats sore from singing and cheering.

As for the organiser, he occasionally passes round with an old tin for contributions but the point was not to make money, he insisted.

"I didn't put any thought at all into what would happen in the future ... I maybe just had the idea that something funny could happen out of it."

Axel Puell, head of the "Friends of the Mauerpark" association, as the park is called in German, welcomed the attention the Irishman has brought to the area, as the karaoke has also become a fixture on the tourist trail.

"With his karaoke, Joe has shown that you can succeed without any commercial logic behind you whatsoever," Puell told AFP.

"There's nothing to win, it's free to take part and there's no advertising for it."

However, Puell worried that the success might have a limited shelf-life.

"One day, Joe might want to do something else. And then, it's very likely that some commercial venture will come in its place."

But for now, the murdering of classic hits continues unabated in the place where border guards once had orders to shoot-to-kill.

And as the sun reaches its height, the crowd takes up perhaps the most appropriate refrain of all, from Pink Floyd's "The Wall."

"All in all, it's just another brick in the Wall..."