a common shamanic concept, and a universally told story, is that of the healer traversing the axis mundi to bring back knowledge from the other world. it may be seen in the stories from odin and the world ash tree to the garden of eden and jacob's ladder to jack and the beanstalk and rapunzel. it is the essence of the journey described in "the divine comedy" by dante alighieri. the epic poem relates its hero's descent and ascent through a series of spiral structures that take him from through the core of the earth, from the depths of hell to celestial paradise.