From giant murals emblazoned on towering building facades to delicate stencils subtly decorating power boxes or subway stations: Urban Art is transforming the urban fabric into an omnipresent open-air gallery. Despite, or perhaps precisely because of, their transience, these works of art characterize the city - and the city in turn characterizes its artists. They cut portraits out of stone, draw delicate ornaments, create three-dimensional installations, or spray photo-realistic paintings and imaginative figures - sometimes politically motivated and illegal, sometimes as homage to their own creativity and artistic freedom, or sometimes as a commissioned work.