"The thing with trends is, somebody is doing their thing, and then suddenly everybody is doing the same thing, and it's getting boring. But that's how our underground stays alive."

"Take the boutiques," says Tassilo. "The owners like to hire foreigners who don't speak German or speak it with an accent. The thicker the accent, the better. It's good to be an American or Chinese or Persian - anything exotic.

"The customers think they're getting some secret fashion tip. The freak look is long dead, and people are buying clothes again. They hope they're buying something really different."

The same psychology explains the mysterious yellow bananas which brighten many of Cologne's grey-faced buildings.

About four years ago, an anonymous graffitti artist began spraying crude bananas on the outside of galleries, Tassilo explains. People didn't know what was going on. They decided the bananas symbolized a "rebel" gallery, and the crowds turned up in droves.

Soon, gallery owners paid the graffitti artist to mark them with a banana. The gross commercialization of the little yellow bananas upset a lot of people, especially "pure" graffitti artists. Black slash marks began appearing on the bananas - either symbolizing disapproval or that the gallery was closed.