A visitor takes photos of a work of U.S. artist Andy Warhol at a preview of the \"Andy Warhol : 15 Minutes Eternal\" exhibition at the Power Station of Art in Shanghai, east China, April 19, 2013. The exhibition, featuring more than 400 works of Warhol and spanning from his career from 1940s to 1980s, will be opened on April 29, 2013.