Spontaneous, in-your-face and unauthorised, the work of street artists and graffiti writers demands our attention. Wildly creative and often subversive, street art shows that just because a work isn't in a gallery doesn't mean it's not art. From Sao Paolo to Sydney, New York to Tokyo, these artists exhibit their work in the world's most accessible museum - the street - sharing their vision with a public unable to avoid their work, like it or not. At its best, street art is not simply about slogans or personal promotion but is playful, creative and often beautiful, drawing on the energy of its surroundings. The World Atlas of Street Art and Graffiti focuses on the most prolific and interesting artists from around the globe - including 12 Australians. Have a look at the 15 street art spots you must visit as reported in the Huffington Post