A giant new exhibition space created by famed graffiti artist Banksy opens to the public on May 3, 2008 in London, England. The disused tunnel beneath Waterloo station has been transformed by 30 artists from around the world. The three day event, tagged as the “Cans festival”, also invites the public to add their own stencil art. (Photo by Jim Dyson/Getty Images)

Two men chat under a floral skull artwork by “Part2ism” in the “One Foot in the Grove” exhibition of street art by “Mutate Britain” under the Westway flyover on October 6, 2009 in London, England. The exhibition features: sculptures, paintings, stencils and graffiti from some of the world's most prominent street artists. The event, which is in its second year, is expected to draw in over 5000 visitors. (Photo by Oli Scarff/Getty Images)

A stencil art piece of a buddha in a neck brace at giant new exhibition space created by famed graffiti artist Banksy, on May 7, 2008 in London, England. (Photo by Jim Dyson/Getty Images)

A subway painted by stencil artists at a giant new exhibition space created by famed graffiti artist Banksy, on May 7, 2008 in London, England. (Photo by Jim Dyson/Getty Images)

Grafitti by the illusive artist Banksy adorns a buildingAugust 28, 2008 in New Orleans, Louisiana. New works by the artist, whose paintings are also sold in galleries, have been popping up throughout New Orleans coinciding with the third anniversary of Hurricane Katrina. (Photo by Sean Gardner/Getty Images)

Stencil artists paint the walls of a subway as a giant new exhibition space created by famed graffiti artist Banksy opens to the public on May 3, 2008 in London, England. (Photo by Jim Dyson/Getty Images)

Grafitti by the illusive artist Banksy adorns a closed shop August 28, 2008 in New Orleans, Louisiana. (Photo by Sean Gardner/Getty Images)

Graffiti artist Stae poses for a picture as he completes the finishing touches to a World Cup themed house he is decorating in a street in the Knowle West area on June 11, 2010 in Bristol , England. (Photo by Matt Cardy/Getty Images)

People pass by a wall with graffiti at the entrance to the recently “pacified” Babilфnia slum, or favela, on December 3, 2009 in Rio de Janeiro, Brazil. Babilфnia is one of a number of Favelas in Rio where the police are attempting a softer touch by participating in community policing after they clear the area of drug gangs. It is believed that the police want to continue with these programs citywide ahead of the 2016 Olympic Games. As Brazil prepares to host the 2016 Summer Olympics international scrutiny is falling on Rio de Janeiro`s favelas where over 5,000 people were murdered last year alone. In the last week violence in tourist areas has increased as drug gangs are increasingly reacting to an increased police presence in the favelas. In figures released Tuesday by the IBGE (Instituto Brasileiro de Geografia e Estatнstica) statistics agency it was found that an average of 68 young Brazilian men died violently each day between 1998 and 2008. These numbers included murder, traffic accidents and gang violence involving the police. (Photo by Spencer Platt/Getty Images)

Grafitti by the illusive artist Banksy adorns the levee wall in the Lower Ninth Ward on August 29, 2008 in New Orleans, Louisiana. (Photo by Chris Graythen/Getty Images)

Pedestrians walk by a new mural by the graffiti artist Kenny Scharf on November 30, 2010 in New York City. The mural, which is located on Bowery Street, is part of an ongoing project in which a variety of artists are invited to decorate the wall as part of a series. The wall is owned by Tony Goldman. (Photo by Spencer Platt/Getty Images)