Call to Secure Nuclear Material at Seoul Summit Listen Download Embed Share Share this on Facebook (Opens in a new window) Share this on Twitter (Opens in a new window) Share this via Email U.S. President Barack Obama arrives at the Seoul Airport for the 2010 G20 Summit on November 10, 2010 in Seoul, South Korea. ( Chung Sung-Jun / Getty ) Produced by Javier Guzman Produced by PRI and WNYC