Although Christmas celebrations are over in many western countries by December 25th, for millions of Orthodox Christians the 7th of January marks the biggest day of celebration. The reason why these dates are different is because of the calendars used to calculate the dates of the birth of Jesus. The BBC's Olga Ivshina explains. #orthodoxchristmas #christmascelebration Subscribe to #BBCMyWorld here: https://bit.ly/3wxzdPx