War Diary WW2 for Monday, December 25, 1939:
Western Front
Hitler on 3-day visit.
Finland
Winter War: On a cold Christmas Day (-30 °C), Helsinki, Viipuri and over 30 other Finnish towns and villages bombed or strafed, railways also attacked. Finnish fighters and AA guns destroy or damage 20 bombers.
Home Fronts
Britain: The King broadcasts a Christmas message to the Empire.