What happens when you look at graffiti and street art as unlimited art forms instead of urban phenomena? Concrete Canvas does just that; investigating the media the artists work with, the canvases they work on, the themes that arise through their work, and the way their art redefines the spaces in which it is set. Concrete Canvas is filled with stunning photos of works from new and exciting artists, as well as established names, including Ron English, Phlegm, Daim, Invader and more. It examines how the curation of public space is affecting our cities and moving art into the future. Global Street Art is the largest online archive of street art photography. Here, its founder Lee Bofkin shares some of his best stories of documenting street art.