The skiers are actually going skiing. They are already testing the slopes on the steep roof of the new waste incineration plant. Without snow, but on a synthetic turf structure, grassland and silicone. Even if it is artificially created, the mountain calls! Copenhill is the name of this worldwide unique attraction, which lures tourists and locals, architecture fans and winter sports enthusiasts, school classes and old snow hares to the island of Amager. Unlike alpine skiing, the journey here is relatively easy, at least for all Danes. Copenhill is only ten minutes by bicycle from the Free State of Christiania, and only 15 minutes by car from Copenhagen Central Station. "This is the fastest we Danes have ever been able to reach the slopes," says Christian Ingels with delight. His eyes are twinkling, he has pushed his sunglasses high up in his head. The tinted goggles sparkle in the sun. The father of this curious project was practically brought up on skis and describes himself as a true winter sports fan. In 2009 he and his great cousin, the architect Bjarke Ingels, won the competition to come up with a future use for the roof on the new waste incineration plant. "Copenhill is created by skiers for skiers," he says, emphasising the vision. Ten years later, the time has come. The project, which at first sounds like a twisted joke, has been implemented. Copenhagen now has a ski slope.

Carsten is at the summit with his snowbike. He and his friends Tobias and Eric have been invited to test the slope. Above them blue sky, below them a gigantic colossus of concrete and steel, in front of them the pleasure of the 450-metre descent. Like Christian and many other Danes, the man in his mid-forties has been a skiing enthusiast since childhood – after an accident he switched to a snow bike. On three runners, arranged like a tricycle, he swings onto the piste and glides down the slope in fast turns. The plastic mats that skiers descend on produce almost the same noise as freshly pressed snow in the morning. For the most realistic snow feeling possible, the boards are treated with silicone instead of wax – a strange idea for the skiers and snowboarders, but the way to achieve an authentic experience on the slopes. "You quickly get used to it", explains Tobias, an enthusiastic snowboarder who has descended the piste many times before. It is more irritating that you don't see a white surface, but a green one, he laughs. The two of them put on their gloves and get ready for the next descent.