Originally, under the Julian calendar, December 25 was the day of the winter solstice and the day Christmas was celebrated. In 1582 the Gregorian calendar was implemented and as such December 25 came a few days later than the solstice event.
*Winter solstice for North America.. summer for the south.
The UK’s National Physics Laboratory made the world’s smallest Christmas card, using platinum-coated silicon nitride. It measures just 15 microns wide. You can fit 200 million of these on a postage stamp.
