Security agents check equipment of reporters coming to cover the G20 summit at Mellon Arena, Pittsburgh. All media must pass through a security screening checkpoint at Mellon Arena, which is several blocks away from the summit venue at David L. Lawrence Convention Center. Leaders of the world’s biggest economies will meet at the convention center on Friday (US eastern standard time) to discuss such issues as global economic recovery, reform of the international financial system, climate change and trade protectionism. [Huang Xiangyang]