Winter Solstice was celebrated in the British Isles in a very special way. Many of the great monuments were built to track the sun. Many of the mounds are oriented so that the sun enters their long entrance ways and illuminates their inner chamber on the solstice. The Winter Solstice represents the rebirth or rekindling of the light, the sun. This process reminds me of the conception of the Solar Hero, the Christ.
Here’s a site that shows the beginning of this process at Newgrange on December 18th.