A commuter peers out of a bus window in Seoul, South Korea, at police officers lining the streets on the first day of the G-20 summit, where world leaders including US President Barack Obama and German Chancellor Angela Merkel are meeting. Around 20,000 anti-G-20 protestors clashed with authorities at a rally on Sunday in Seoul's city center. First-time host South Korea has organized a force of around 60,000 police officers for the summit, including 10,000 riot police. World leaders are in the South Korean capital to discuss the global financial system and world economy. South Korea is the first country in Asia and the first non-G-8 country to host the G-20 summit.