Cidade Cinza / Grey City

She will never win a beauty competition – São Paulo, a city of monotonous façades, chaos and noise. It is not entirely by accident that street art found fertile ground here and grew with surprising vigour. Graffiti artists such as OsGêmeos and Nunca have established a new style, the quality and creativity of which has astounded galleries worldwide. But when the sprayers returned from an exhibition at London’s Tate Modern in 2008, they found their work had been over painted in grey. This "cleaning" operation by the city immediately triggered a broad public debate.