WHEN Frankfurt social worker Stefan Mohr needed a new location for the troubled children he works with to express themselves through spray paint and graffiti, it did not take him long to find a potential site. The trouble was, the vast area of fencing he found was around the site on which the European Central Bank's new €1bn headquarters was being built.
Mr Mohr contacted the bank. To his surprise, it not only agreed to let him use the fence around one of Europe's biggest building sites for graffiti, it offered €10,000 to pay for wooden panels to be attached to the fence, and for supplies of spray paint.
Mr Mohr said he thought from the start that the homeless and underprivileged young people he works with would get a kick out of spraying on the site of such a politically symbolic building.
But he had no idea that some of the world's most famous graffiti artists would help turn the fence into one of Frankfurt's biggest tourist attractions.
"All we wanted to do was find a place for kids to express themselves and show the public that graffiti is art, not vandalism," Mr Mohr said.
"It has proved amazingly popular, with people coming from across the world to paint and take photos, and pictures from the wall are used in the press all over the world."
The graffiti, which is often highly political and includes caricatures of ECB president Mario Draghi and German Chancellor Angela Merkel, has proved so popular that dozens of banks and money managers have been interested in buying the works.
"A lot of people want to buy pieces, but we didn't do this to make money," Mr Mohr said. "We don't want to sell them. We like to see the pictures painted over. That's how graffiti works."
However, their landlord, the ECB, was allowed to buy one of the first works, showing two cocks fighting, and will display the piece inside the building when it opens in 2014.
Another artwork was sold after an investment fund owned by computer billionaire Michael Dell hired investigators to track down the artist behind a piece inspired by the Bond film Casino Royale. It shows Mr Draghi and Mrs Merkel as 007 and a Bond girl inside a casino. The painting, on plywood, now hangs in the Manhattan office of MSD Capital.