Big hitters arriving for the G20 summit. Head of the IMF Christine Lagarde was among the first to land in St Petersburg. The Group of 20 cut its teeth during the financial crisis - working to improve cooperation between developed and emerging economies on economic issues. This time, Syria is firmly at the top of the agenda. US President Obama - visiting Sweden ahead of the summit - said he was hopeful the G20 host, Russian President Vladimir Putin, would change his position on Syria.