Really? I'd disagree. Then again, I'm sure we'd all find our own worlds less interesting by virtue of being familiar with them.

I suppose one of the simpler stories would be that of Gemini. According to the legend, the king of the Greek Gods, Zeus, fathered twin sons named Castor and Pollux by a mortal woman. [let's not go into how that happened, it's kind of insane] They grew up to become legendary heroes who featured in various other myths, until Castor was fatally wounded in a feud with their cousins. Rather than be separated from his brother through death, Pollux petitioned Zeus to give Castor immortality, and so they were placed in the heavens.