Today, on the 21st of December 2021, at 15:59 UTC, an astronomical event called solstice has occurred. For the northern hemisphere, it’s called the winter solstice, and it marks the shortest day and the longest night of the year. From that moment onwards, the days in the northern hemisphere will keep getting longer, and the nights shorter. It is also the beginning of the astronomical winter.
The winter and summer solstices are celebrated in many different cultures. Stonehenge, a prehistoric monument produced by a culture that left no written records, is aligned to the sunset of the winter solstice and the opposing sunrise of the summer solstice.
NASA published a blog post that explains the mechanics of the event.
The photo has been taken at precisely 15:59 UTC in Novigrad, Istria, Croatia. Even though the day was cloudy, the sunset at that time was partially visible.