Tehran, Dec 20, IRNA -- Millions of Iranians all over the world Monday night will celebrate 'Yalda', the longest night of the year and the first night of winter as a token of victory of the angel of goodness over the devil of badness. 'Yalda' is a Syriac word meaning birth and according to Mithraism, a faith that initially originated from Persia and later spread out throughout the ancient civilized world, the first day of winter which falls on December 21 this year, was celebrated as the birthday of Mithra, the angel of light. Ancient Iranians believed that two groups...