Germany? Celtic culture? Scandinavia? Ask anybody where the Christmas tradition of decorating a tree with colorful balls, fairy lights, painted eggs, and small figures comes from and they probably won’t know the exact answer.
The Celtic tradition speaks of Idrasil, the Tree of the Universe, which was supposed to link heaven and hell. The tree used to be decorated in order to honor Frey, the sun god, whose birth coincides with the Christmas season.