VATICAN CITY — The Vatican on Friday turned the lights on a towering fir tree for Christmas in St. Peter's Square.The 30-meter-high (100-foot) tree comes from the woods on the slopes of a valley in the South Tyrol, Italy's German-Italian speaking region in the north.Rows of gold and white lights draped the tree looking like elegant necklaces.The square, usually busy with tourists, was largely deserted when the lights went on Friday evening.