They might appear to have little in common with statues or obelisks, but graffiti images serve a vital public function. What do you think of when you hear the word ‘graffiti’? Something vandalistic, illegal, illegible? Something dirty or threatening? Something that lowers property prices and instils fear? If this is what comes to mind, you’ll undoubtedly (and sadly, for me) be in the vast majority, the term today being used as a shorthand for urban decay and danger. Now what, likewise, do you think of when you hear the word ‘monument’? Something heroic, classical, important? Something large and permanent? Something placed in the esteemed districts of the city and venerated by the worthy? If this is what comes to mind, once more you’d be in the majority, the term today almost immediately suggesting a public artefact upholding (often literally) the best our societies have to offer.