Christmas or Christmas Day is an annual festival commemorating the birth of Jesus, observed most commonly on December 25 as a religious and cultural celebration among billions of people around the world.

With the spread of Christianity beyond Europe and North America, the celebration of Christmas was transferred to societies throughout the non-Western world.

In most European countries, gifts are exchanged on Christmas Eve, December 24, keeping with the notion that the baby Jesus was born on the night of the 24th. However, the morning of December 25 has become the time for the exchange of gifts in North America.

From Wikipedia