Street Art, what is it?

Put simply, street art is any art that uses the streets instead of a gallery. This can be graffiti, stencil art, installations, sculpture, stickers, posters, projections, and even covering yarn-bombing (woollen knitting added to the environment). It is typically not endorsed by any official organisations, very often having to be put in place against the local laws.  Some have become world famous, such as Shepard Fairey and Banksy. Others, such as Espo, are famous within the graffiti community.