A woman walks past graffiti on shopkeepers' shutters on February 8, 2011 in Madrid. The Spanish capital have invited graffiti artists to paint the steel shutters protecting their stores at night in the hope this will stop them from being defaced by crude scribblings made on the run. Over 130 graffiti artists from across Europe, including Bristol and Milan, decorated 140 shutters on February 6, 2011 in Madrid's central Malasana neighbourhood, which has long been the heart of the city's countercultural scene. Since painting over another graffiti artists' artwork, especially with lower quality work, is considered a serious insult by street artists, the shopkeepers believe they will no longer wake up to find their shutters covered with ugly, and sometimes obscene, drawings that can be expensive to remove.