Street art isn't just gang tags — it can revitalize and beautify urban spaces, increase community identity, and even be a form of nonviolent protest. The work of Edina Tokodi kind of does all of those, plus it's about as green as graffiti can be: Tokodi's studio Mosstika makes street art from living moss.
More photos on Tokodi's Flickr stream and the Mosstika webpage.