President Obama Hosts World Leaders At Nuclear Security Summit

WASHINGTON - APRIL 13: (R-L) U.S. Chief of Protocol Ambassador Capricia Marshall shows the way to Director General of the International Atomic Energy Agency Yukiya Amano, Secretary-General of the United Nations Ban Ki-moon, and Deputy Prime Minister and Minister of Intelligence and Atomic Energy of Israel Dan Meridor, during the group photo session of the Nuclear Security Summit April 13, 2010 in Washington, DC. Forty-seven countries have gathered at the invitation of the U.S. government to talk about nuclear safety and how to make dangerous materials less accessible to terrorists. (Photo by Alex Wong/Getty Images)