20. JR

Yes, the JR buzz has certainly died down since the artist's whirlwind 2011. Still, the 2011 TED Prize recipient was busy. Notably, he took a coveted month on the Houston and Bowery Mural Wall in NYC, as well as promoting photo based public art through his own "Photo Booth" installation at Paris' Centre Georges Pompidou. Allowing visitors to create their own art and mimic his own trademark style, JR encouraged the power of art as a vehicle for social change.