The winter solstice is the moment when the sun reaches minimum declination. This results in the shortest day and longest night of the year, in the northern hemisphere. Since ancient times, this day has been recognized in various ways and celebrated by different religions and cultures. One thing they have in common is sacrificing for the light to return and for achieving god’s blessings for the next agricultural year. The winter solstice usually occurs around December 21th during the so-called Thomas day. It used to be a public holiday in Sweden until 1772.