Obama's Biggest Global Moments

The images that defined Obama's first four years on the world stage, with reflections from those who were intimately involved in shaping them.

JANUARY 21, 2013

Prague nuclear weapons speech (April 2009)

In the Prague speech I outlined a vision of a world without nuclear weapons, but said that that was unlikely to be achieved even during my lifetime. But I said that there were a series of specific steps that we could start taking to move in a direction that lessens the threat of nuclear weapons.

-- President Barack Obama, April 5, 2010 

SAUL LOEB/AFP/Getty Images