I noticed that the story of Gilgamesh was mentioned, which is a fabulous tale that I have much enjoyed reading, but I just had to say that I think one of my favorite works of mythology that I have read, and one which has stuck out within my mind the most is the Inanna's Decent There is just something about this story that I think is fabulous and I adore the tale.
It is the story of the Goddess Inanna whom decides to descend into the underworld, where her sister reigns. And there is this marvelous scene in which to inter the underworld she must pass through seven gates and at each gate she must remove a piece of her clothing until when she appears to her sister at the throne of the Underworld, she is humbled before her, completely nude.
And when it comes time for Inanna to return back to Heaven, where she rules, she reverses the process, and passes back through the gates, dressing herself on the way, so she can emerge reborn into the world.
It is very symbolic of the mother's womb, and the process of birth and death, and rebirth.
The story can be read here: