Celtic tattoos: They're very beautiful, and it's said the more detailed the knot (assuming it's a Celtic knot tattoo), the more powerful it is.
The Celtic knot is tied to an infinity sign with a tribal design. Both of these are indicitive of infinity or great potential with the Celtic knot a symbol of love (though not in a heart or clasped hands design).
Celtic tattoos can symbolize sacks of things, depending on the knot. Most often they are believed to provide protection, attract or declare love, or (Surprise!) used purely for decorative purposes.
Some of the knotwork is dizzying in its complexity, but I think the result is beautiful. It would probably look more 'right' on me, as I come from Celtic heritage.
