The spiral is probably the oldest known symbol of human spirituality. The spiral has been in rock carvings thousands of years old, on every continent in the world. The religious significance can only be guessed at, but it has been found on tombs, and almost certainly has a connection with the sun, which traces a spiral shape every three months in its travels. The double spiral found in neolithic Celtic stone art also follows the path of the sun, describing the movements of the heavenly body over the course of a solar year.
A triple spiral motif found on Celtic tombs is drawn unicursally (that is, in one continuous line), suggesting a cycle of rebirth or resurrection. (this hypothesis is bolstered by the fact that many of these appear to be deliberately placed where they catch the first rays of the sun on the solstice). The sun, dying and rising every day, is a natural symbol of rebirth, and the triple spiral gives an obvious connection between the solar symbolism and the nine months of human gestation. In modern times, the spiral is still spiritually significant. The spiral is the symbol of spirit in Wicca, an emblem of the Goddess.