U.S. President Barack Obama,left. smiles with Italian Prime Minister Silvio Berlusconi, centre, and Russian President Dmitry Medvedev during a group photo at the G20 Summit in the Excel centre in London, Thursday, April 2, 2009. The objective of the London Summit is to bring the world 's biggest economies together to help restore global economic growth through enhanced international coordination. AP Photo/Kirsty Wigglesworth
