Inside Berghain's Pop Kultur festival

"You have two choices. You can stay here forever, or you can be re-programmed. I'm not sure which is worse." Mixmag has been in Berghain for three days straight. We're confident both of the above have now occurred. There are casualties. A journalist we befriended has climbed a tree and refuses to get down. A German PR is telling us, tearfully, why she has to break up with a guy she wasn't seeing anyway. A label scout is angrily debating with the tree-based journo about the difference between rock music that's 'thrusting, yet non sexual' versus 'conventionally thrusting'. The bar in the smoking area serves half pints of prosecco. We've just offered a cigarette to an art installation.

The second instalment of Berlin's Pop Kultur festival is the first event of its type allowed access to the world's most mysterious nightclub. A metaphor for the state of modern music and the media in general, the sheer novelty of Berghain's refusal to do guestlist, do VIP, do press or even allow photographers into their usual nights has made it more famous than any PR campaign ever could.

Deep in the belly of an East German ex-power station is a series of high-ceilinged rooms and steel stairways. Hot, focussed floodlights fling the entire place into patches of blazing light and pitch dark. Doors are manned by laid-back bouncers checking phones have a sticker over the camera. The lighting for each performance is equally stripped back, artists backed not by an LED wall by their own dancing shadows on the wall behind. The whole venue is devoid of any kind of decoration save a single, minute painting of the Ancient Egyptian Eye of Horus, tucked on a side ledge 60 feet up above the main floor. It is a symbol offering protection for those entering a parallel reality.

"People come here fleeing places where they could not afford to keep creating. We set Pop-Kultur up in part to help promote young, emerging artists, and to introduce them to other artists too," explains Pop-Kultur founder Martin, who in jeans and tattered blazer recalls a uni lecturer who hasn't slept in a while. It explains the line-up. To start with, it's light on techno. There are of, course, injections of it: a few of Matthew Herbert's "7,429 kick drums" meshed with samples taken from crowd recordings; Inga Copeland's set featuring a build so long it was dubbed "'friendzone techno'" by one wag, "because it ain't ever gonna happen"; Pantha Du Prince's vocal chop-heavy electronica workout.

But there are also talks on the concept of art, short films, electronica, US rapcore and Spanish rock bands fusing to create something complex – a fact pointed out by the front man of Ho99o9 as he stands in the centre of the floor, discussing music mid-set with a member of the crowd. Stark naked. Another member of the group, a 6' 5" man built like a truck, wears ripped denims and an eyeless black balaclava. He gives us a cheerful wave.

Shaken, for reasons we don't fully grasp, but expect were intentional, we head back out for a smoke. Elijah Wood is playing a Turkish funk set upstairs. The tree journo is beatboxing at a wall. Talk moves to the concept of Berlin (and Berghain) "changing" – at which there's generally laughter. "People think Berlin's culture movement is a relatively new thing. It's not. Berlin was always a place of great creative momentum," says Martin. It's a view shared across the board. While Berghain may seem to some like the latest 'buzz club', with nay-sayers predicting an inevitable sell-out phase, "Berghain has always been the absolute centre for us," says promoter Maximilian. "The international media may come and go, but we'll still be here".

So what of the tales of mass movements of Brits into Berlin, bringing rising prices? "Our problem has never, will never be tourists. It was these that made Berlin the city it is today. Our only problem is idiots. Which, we understand, are a problem in every city," say label owners Dan and Dom. It seems Berlin, the city where it's easier to get hallucinogens than non-soy-based milk, isn't about to be rocked by a few enterprising shufflers.

We move back inside where the place reverberates with kicks, snares and a sense of shiveringly sexy sleaze. The outfits are from the 1970s. The crowd range from 19 to mid-50s. We're chain-smoking and being handed shots by total strangers. We've spent three days here now, and we're starting to get the context, starting to nail the angle. It's a musical fortress, a cultural hospice, famously liberal yet utterly uncompromising. Seems to us that Berghain's message to the world is simple: we're here. We've always been here, and we'll be here after you've gone. So get back in the queue.

This feature is taken from the November issue of Mixmag, onsale now