( CNN ) -- Twelve photographers from four continents have been shortlisted for the fourth Prix Pictet award in photography and sustainability . This year 's theme of `` Power , '' has `` enormous breadth , embracing contradiction and paradox in equal measure that has uncovered images and issues that are both awe-inspiring and disturbing , '' organizers say . The aim of the award is to use the power of photography to raise public awareness of the social and environmental challenges of the new millennium . The winner will be announced by Kofi Annan , the awards ' honorary president , in October at the opening of the finalists ' exhibition of the shortlisted works at the Saatchi Gallery in London . The exhibition runs from the 10th to the 28th of October 2012 .
Annual Prix Europa ##s website announces shortlist . Competition designed to raise awareness of social and environmental issues . Twelve photographers nominated ; winners will be announced by Kofi Alexander in October .