U.S. President Barack Obama waves as he departs from Prague's Ruzyne Airport

 
U.S. President Barack Obama waves as he departs from Prague
U.S. President Barack Obama waves as he departs from Prague's Ruzyne Airport April 9, 2010. The United States and Russia signed a landmark disarmament treaty on Thursday they hope will herald better bilateral ties and raise pressure on countries seeking nuclear weapons to renounce such ambitions. REUTERS/David W Cerny (CZECH REPUBLIC - Tags: POLITICS)