• ranian children build model centrifuges out of styrofoam and glue in a competition beneath a banner reading 'Nuclear scientists of the next generation,' as Iranians stage a mass rally to mark the 35th anniversary of the 1979 Islamic revolution on February 11, 2014 in Tehran, Iran.

    Preliminary negotiations in Vienna over Tehran's nuclear program said to go well, even if skepticism about a long-term deal remains.

    LAST UPDATE : Feb 20, 2014, 1:14 PM EST