Vegvisir ("the viking compass"). It is said that if this sign is carried, one will never lose one's way in storms or bad weather, even when the way is not known. It is encircled by protection runes. This would be a cool tattoo.
If you hear the word “Viking” and imagine a man with a huge, out of control, lice-ridden beard with smelly bits of food (or fleshy battle shrapnel) stuck in it, you’re going to need to forget all that.