In Ireland there is a passage tomb called Newgrange. It's the oldest known man-made structure on the planet. On one day of the year--winter solstice--the rising sun shines through the doorway and up the passage to the center chamber. (You can see a short informative clip here, it has clearer images than the embedded one, and also shows just how small and claustrophobic the place is. It wasn't really on solstice though--they have an electric light they use to demonstrate for tourists...the embedded film below is the real thing, which is why I included it here):
(this movie is a 6min compilation taken from the live filming of the event in 2007)
Winter Solstice is the shortest day, and longest night of the year. Although it is traditionally a pagan holiday, I like the idea of celebrating it too, and here is why.
It is the day when darkness begins to recede and light returns--like Christ's Light conquering the darkness of evil.
It reminds me that the darkness of sin can be replace with the light of repentance and forgiveness.
It is a reminder that the darkness of death is only temporary, and will be followed by the light of resurrection.
In short, Winter Solstice reminds me of the Greatest Light of All.