Germanic tribes believed that humans came from trees. They imagined creation to be a giant ash tree that reached into the heavens. This world tree they named Yggdrasil. The world tree had three strong roots. One reached into Midgard where humans dwelled. The other to Jotunheim to the giants, and the third reached down into the underworld.
Every kind of evil threatened the tree. At the root growing deep into the underworld, Ridhogt, an evil dragon, gnawed incessantly, as did other hideous creatures. Four deer and the goat Heidrun feasted on the leafy foliage of the ash tree. A huge eagle sat on the top of the tree, and a nimble squirrel ran ceaselessly back and forth between it and the dragon gnawing at the root.
