(L'Osservatore Romano/Pool Photo via AP) Pope Francis meets participants in the International symposium on a nuclear-weapons-free world, at the Vatican, Friday, Nov. 10, 2017. The Vatican hosted Nobel laureates, U.N. and NATO officials and a handful of nuclear powers at a conference aimed at galvanizing support for a global shift from the Cold War era policy of nuclear deterrence to one of total nuclear disarmament.