P5+1 and Iran representative pose prior to the announcement of an agreement on Iran nuclear talks on April 2, 2015 at the The Swiss Federal Institutes of Technology (EPFL) in Lausanne. Iran and world powers said they had reached agreement on Thursday on 'key parameters' of a potentially historic deal aimed at preventing Tehran from building the bomb. AFP PHOTO / FABRICE COFFRINI        (Photo credit should read FABRICE COFFRINI/AFP/Getty Images)