Some people want to make the world a better place. Some people want to make the world a better looking place.
(Banksy)
Graffiti originated from young people in the early 70s in New York as a means of communicating the distress of poor neighborhoods. Today street art, rather than graffiti, is an object of interest for galleries and museums. The tools of the trade are sprays, posters, stencils, rollers, stickers, mix media, tagging, writing.