Christmas is an annual festival commemorating the birth of Jesus Christ, observed primarily on December 25 as a religious and cultural celebration among billions of people around the world. Christmas is an annual festival commemorating the birth of Jesus Christ, observed primarily on. Christmas Day, on December 25, is one of the most festive Christian holidays in many countries around the world. 'Wonder Woman 1984' delayed again, will arrive in theaters Christmas Day. Many people in the United States celebrate Christmas Day on December 25. Given the importance of Christmas as one of the major Christian feast days, most European countries observe, under Christian influence,.