Image copyright Carolin Saage Image caption Ravers are still taking to the Berlin dance floors, as pictured at the Konfettinacht club in 2007

Thirty years after the fall of the Berlin Wall, some of the city's clubbers and DJs recall how illegal raves helped bring a once divided nation back together.

Berlin today is a temple for dance music fans from all corners of the globe, ready to leave their prejudices at the nightclub door and collectively surrender to the beat.

There was a time not so long ago though when scenes of this nature were a physical and ideological impossibility.

While baggy ravers in the UK were coming together for an extended Second Summer of Love, people in the German capital remained divided by a 27-mile wall.

After it came down on 9 November 1989, as well as rubble and dust, there was a sudden explosion of underground parties in vacant buildings, train stations and power plants.

Unlike the discos of old, these ecstasy-fuelled nights took their lead from the new sounds of Detroit techno and Chicago acid house, while emulating the free-spirited experience of parties in Ibiza and at Manchester's Hacienda club.

'Utopian'

Heiko Hoffmann, who was a teenager at the time, said the "massive shift" to rave culture instantly "changed my life".

Previously, West Berliners like him were only able to visit the east with a day pass. Generally speaking, people in the east could not cross the border.

"Just a couple of weeks after the fall of the wall I was dancing in industrial ruins next to people from the east, who just a couple of months earlier I wouldn't have been able to meet," says Hoffmann, the co-curator of the new No Photos on the Dance Floor! exhibition.

"All of this was happening to mostly very raw techno music," he adds, explaining that the name of the collection refers to the prevailing culture of protecting revellers from the judgement of the all-seeing camera.

"If someone would tell you today that next week North and South Korea would be reunited, and a radical new form of music that you didn't know existed before would be coming, and people would be dancing together in spaces that were new and unused for both of them, you would think that's completely utopian.

"That's what happened 30 years ago."

Image copyright Martin Eberle Image caption Outside Tresor nightclub, which was built in the vaults of a former department store next to Potsdammer Platz - a literal no-man's land during the partition.

Wild nights in often temporary and industrial spaces near where the wall had stood - from Potsdamer Platz to Friedrichshain - fitted the primitive music and light/sound systems perfectly.

Hoffmann believes the conditions were ripe for this unique scene to grow, because there was "a social change happening, as well as a musical one."

"Germany was first reunited on the dancefloor of these parties. You didn't really have to make a distinction any longer between east and west.

"I think it's crucial that it was not people from East Berlin dancing to music that was already around, or going to spaces that were West Berlin spaces, but it was really that people from the west and east could discover something radically new together."

'A friendly revolution'

It took almost a year for Germany to be officially re-unified in October 1990, and even then there were still plenty of legal grey areas.

East Berliner Sebastian Szary, of electronic music duo Modeselektor, recalls how budding young DJs and party people like himself at the time took full advantage.

"Anything was possible because there was no rule, the government was still in a grey zone - in a no-man's land - and the law was not written," he says.

"The re-unification was done but there were a lot of things which were unclear. Like the police knew there were illegal parties but [they said] 'We don't know what do - let them do the party!'"

People from the UK and across western Europe soon "found the playground to make dreams happen", forming collectives, while enjoying east Berlin's cheap rent and "positive energy".

Image copyright Birgit Kaulfuss Image caption Sebastian Szary (right) and east Berlin schoolmate Gernot Bronsert formed Berlin electronic duo Modeselektor

"I'm 100% sure that is was the result of a friendly revolution," he adds.

"There was a chance the revolution was going to go in another direction with riots and war - it was really close.

"For the next four years there were an uncountable amount of illegal parties, some in forests for hundreds and thousands, and also the Love Parade was growing."

Image copyright Matthias Roeingh Image caption An aerial shot of Love Parade 2003, from the Nineties Berlin exhibition, shows how popular it was

The appetite for a re-unified Germany and the collapse of the Berlin Wall - itself a symbol of the Cold War between Soviet-led communism and the democracies of the West - was already evident at the staging of the first Love Parade festival in July 1989.

It saw 150 people - led by Matthias Roeingh, aka Dr Motte - take to the streets for a demonstration of peace, love and music.

It would become an important part of the rave calendar, in Berlin and beyond, for decades.

Work permit issues forced the parade out of the city from 2007, and ultimately the tragic death of 21 people in a crowd crush in Duisburg in 2010 brought it to an end.

'The re-start of a life'

Quirin Graf Adelmann, whose Nineties Berlin exhibition chronicles the history of the event, stresses mass unemployment in the previously Soviet-run east side of the city made the DIY dance movement an attractive proposition for many.

"Imagine 3.2 million people in Berlin lost their sense of life and the feeling to be useful to society, as there were no jobs," he says.

Image copyright Mike Trobridge Image caption Festival-goers partied in the streets of Berlin and on top of a truck at Love Parade 1992

"All the education of the past 40, 50 years was blown away. People from the age of 16 to 22, starting their professional lives, had seen everything they'd learned about had disappeared."

"So that was the start of of the '90s. And what are you doing when you are free of the old stories and free of education?" he asks.

"You to try to invent yourself, again. It means you have to experience everything, you have to start something new, and that's what many people tried in Berlin.

Image copyright Tilman Brembs Image caption More party people: Dancing at Marco, Insel der Jugend in 1991, from the No Photos on the Dancefloor! exhibition

"On the one hand there was a 20% unemployment rate, and on the other - 50 different nations from everywhere around the world came into Berlin to feel the re-start of a life."

'Queer culture was crucial'

As the scene progressed - and original basement nights like Tekknozid and UFO gave birth to clubs like the legendary Tresor and E-Werk - two things were vitally important in ensuring it could prosper.

Firstly, unlike in the UK and other European nations, Berlin's clubs and bars did not have to close at a particular time, due to the abolition of the curfew in 1949. So parties could go on literally all weekend.

"There are places that have never closed for the last 17 years - they will open 24 hours, seven days," notes Hoffmann.

And secondly, the driving influence of the gay community at venues like Metropol - which had previously been "a Berlin equivalent to Studio 54", he adds, referring to the famous New York nightclub.

Image copyright Wolfgang Tillmans Image caption Clubbers queue for a "sex positive" gay party in 2001 at east Berlin's Snax Club, which still hosts nights at the super-club Berghain

"It was basically the biggest queer discotheque that we had in Berlin. When when the wall came down and the techno scene started, what was great is that the initial parties, they weren't really gay nights or queer nights - but people from all sorts of backgrounds came together," he reminisces.

"So you had football hooligans, and queer [people] and it didn't really matter."

'Influential'

Not everybody was a fan of this newly open party city, but over the next three decades more and more "Easy Jet ravers" - as they became known - flooded in.

Radio anthems by the likes of Scorpions, David Bowie and David Hasselhoff may have initially "put the message out in the world," that "freedom" had arrived in Berlin, but it was this experimental new DJ-led "machine music" that truly soundtracked the era.

As Hoffmann notes in his exhibition, a whole generation of Berlin clubbers "haven't stopped dancing yet", some alongside their own sons and daughters now, at venues like the world-famous Berghain.

Szary, who will perform in London next weekend, is certain you can still hear the influence of techno, breakbeat and '90s Berlin in electronic dance music (EDM) and the pop charts today.

"It's a fundamental part of commercial music now."

"It's a copy of a copy of a copy," he laughs. "But the influence is always there."