The winter solstice is the shortest day And the longest night of the year. In the Northern Hemisphere it takes place between December 20 And the depending on the year. The reverse is true in the in the Southern Hemisphere where the shortest day of the year occurs in June.
Cultures around the world have long held feasts and celebrated holidays around the winter solstice . Fire And light are traditional symbols of celebrations held on the darkest day of the year .

The winter solstice is the day with the fewest hours of daylight And it marks the start of astronomical winter. After the winter solstice days start becoming longer And the nights are shorter And as spring approaches.
Humans may have observed the winter solstice as early as Neolithic period the lasts part of the year of the Stone Age. Beginning about 10’200 BC.
Neolithic monuments such as Newgrange in Ireland And Maeshowe in Scotland are aligned with sunrise on the winter solstice . Some archaeologists have theorized that these tomb-like structures served a religious purpose in which Stone Age people have rituals to capture the sun on the years shortest day.
Stone Age which is oriented toward the winter solstice sunset may have also been a place of December rituals for the Stone Age people.

I got this link from :WWW.History.com