Yalda is the Persian Winter Solstice Celebration which has been popular since ancient times. Yalda is celebrated on the Northern Hemisphere's longest night of the year, that is, on the eve of the Winter Solstice. Depending on the shift of the calendar, Yalda is celebrated on or around December 20 or 21 each year. Yalda has a history as long as the Mithraism religion. Read more