US President Barack Obama (3rd L front) and China's President Xi Jinping (3rd R front) gesture as they gather with German Chancellor Angela Merkel (C front), Russia's President Vladimir Putin (R front) and Turkey's President Recep Tayyip Erdogan (2nd R front) during a group photo before the opening of the G20 Summit at the International Expo Center in Hangzhou on September 4, 2016. G20 leaders confront a sluggish global economy and the winds of populism as they open annual talks, but the long war in Syria and the South China Sea territorial dispute hang over the summit. / AFP PHOTO / GREG BAKERGREG BAKER/AFP/Getty Images