In the heart of Berlin, bang in the middle of a cluster of historic buildings, stands the empty shell of the Palast der Republik, the abandoned parliament of the defunct German Democratic Republic. Built between 1973 and 1976, it was a homage to contemporary communist chic. In its heyday, it housed an enormous concert hall, a theatre, art gallery, conference arena, sports facilities, lounges, restaurants, a discotheque, milk bar and an interior so overwhelmed with elaborate light fittings that it was popularly nicknamed "the lamp shop". But shortly after German reunification, the Palast was discovered to contain dangerous levels of asbestos, swiftly closed and unceremoniously gutted. Today, all that remains of its once-resplendent past is a huge and striking exterior of bronze mirrored glass.
The Palast now faces imminent demolition. In recent years, proposals to save it have involved using the building's shell for exhibitions, installations, raves and theatre performances under the banner Volkspalast ("people's palace"). The latest and last of such ventures is Der Berg ("the mountain"), organised by the Berlin contemporary theatre group Sophiens le. It's an ambitious project, bringing together well-known architects and installation, performance and intervention artists from all over Europe.
Remarkably, in just eight weeks, an enormous mountain has been assembled inside the skeleton of the Palast, in the hope of reopening a debate about the building's fate. The artistic director of Sophiens le, Amelie Deuflhard, explains: "Until now, every performance in the Palast has been overshadowed by arguments about its future. These were seemingly about architecture but in reality were about history, power, politics and the symbolic setting of the centre of the city. For Der Berg, we therefore decided to build anti-architecture and imitate nature by creating a mountain in the building. From the top of a mountain you can get a better view, a clearer perspective."
The journey to the summit of Der Berg is possible via three separate trails: philosopher, pilgrim or mountaineer. Unsure of my German, I tag on blindly to what turns out to be the third trail and follow the group through a small door in a wall. We emerge in a dark minibus with a travelogue for a windscreen. As we chug up the virtual foothills of the mountain, a creature suddenly appears in the road ahead. Our driver hits the brakes, but too late, and the animal (a man-sized minotaur) literally bursts through the film screen and proceeds to savage him in front of our astonished eyes. Amid the commotion, a trapdoor in the roof flies open and we are rescued, surreally summoned aloft by a hearty Austrian in climbing gear.
Der Bergsteigerweg ("the mountaineer's trail") has been created largely by artists and performers from Alpine and mountain countries. By the time we reach the plateau of glorious failure our progress is almost complete. The artists have led us through various ordeals. Some are pure installation - a white box filled with suspended globes through which we crawl, gently fanned by a light breeze from a wind machine. Others are entire esoteric experiences - the Polish group with which we sit down to peel potatoes in reverential silence, carving them into peace signs to be fried and eaten together as a communion. Further along, a provocative group of half-naked drag queens beckons us to be voyeurs of luxuriant joys, a mass of tangled lame and glitter, entwined dopily in each other's arms, constantly kissing one another's bejewelled fingers. Then my personal favourite - a demure, yodelling, pregnant Bavarian Jungfrau, dressed in a dirndl, invites us into her cottage and proceeds to turn psychotic, forcing us to drink schnapps and demanding that we write postcards home, all the time wielding a terrifying power drill.
Yet the building itself leaves the deepest impression. Each trail is peppered with detours through its desolate corridors, rusting metalwork labyrinths and bleak concrete rooms. The climb ends in the Palast's vast main hall, where the summit of the mountain breaks through the roof and rises up into the open sky. The hall once held as many as 5,000 people, but now, like all spaces designed to resound with noise and activity, resonates uneasily with a loud silence. Looking down at the rotting tiers that once seated thousands of spectators is an extremely eerie experience. The air at the summit of the mountain vibrates with the echoes of a million faded conversations.
After the Palast is gone, the government plans to reconstruct the Stadtschloss on the site. This residence of the electors of Brandenburg, opened in 1451, was badly damaged by fire during the Second World War and finally demolished by the East German government in the 1950s. In a city renowned for bold architectural policy, it is hard to understand why the Palast - a potential Musee d'Orsay or Tate Modern - should be replaced with a fake fairy-tale castle from the distant past. Some suggest that, in obliterating the GDR's most prestigious building, the present government is merely trying to punish the old East for problems caused by reunification.
On my descent from the mountain, passing through an empty room that once held a dance hall, a shaft of evening light broke through the enormous bronze windows, absorbing colour as it did so, and the barren space was briefly filled with a lambent, golden sunset. Somehow, it was the most extraordinary moment of all.