December 25 is the 359th day of the year (360th in leap years) in the Gregorian Calendar, with 6 days remaining.
It is the 300th day counting from March 1, every year.
1914 - Just after midnight on Christmas morning, German troops cease firing their guns and artillery and start singing Christmas carols. Crossing the No man's land, they trade gifts with the enemy forces that face them. The truce lasts for three days.
1973 - The ARPANET crashes when a programming bug causes all ARPANET traffic to be routed through the server at Harvard University, causing the server to freeze
1 BC (observed): birth of Jesus Christ, considered to be the Son of God (by Christians); also considered an ascetic prophet of Islam. The date of Christ's birth is celebrated on several different days, worldwide.