Hundreds of millions of people are celebrating Christmas Day, as Orthodox Christians believe Jesus Christ was born on 7 January.
Dozens of countries - from Serbia to Egypt - have been engaging in festive traditions unknown to many around the world. The Orthodox faith goes by the Julian Calendar, while the other major Christian denominations follow the Gregorian calendar.
BBC Monitoring looks at customs observed by Orthodox Christian at Christmas time.
Produced by Alexi Peristianis
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