PYEONGCHANG, South Korea — The opening ceremony of the 23rd Winter Olympics unfurled in frigid temperatures and high spirits Friday, as athletes from the two Koreas marched into the stadium together less than 50 miles from the heavily fortified border between their nations and offered hope of a breakthrough in a tense, geopolitical standoff that has stirred fears of nuclear conflict. The festivities launched what organizers say is the largest Winter Olympics yet, with 92 countries participating. The North and South Korean delegations, marching under one flag, embodied the hopes of a peninsula divided by history and ideology. (MOTOKO RICH, New York Times News Service)