Yggdrasill

an illustration from a 17th century Icelandic manuscript of the Yggdrasill Tree and the creatures that inhabit it.

In Norse mythology, the Yggdrasill Tree or World Tree is a Gigantic ash tree that holds the nine realms of the world together. Its huge branches stretch to the ends of the Earth and to heaven. Its roots dig deep into the Norse's interpretation of Hell.

Mythology

At the top of the tree, there is an unnamed eagle with the hawk, Veðrfölnir, perched on his head, that exchanges harsh words with the Níðhöggr that gnaws at the tree's roots. Ratatöskr, a squirrel takes the messages between the two. Four deer, Dain, Dvalin, Duneyr, and Durathror, gnaw at the buds of the tree. The bottom of Yggsdrasil is populated with snakes, named Goinn, Moinn, Grabak, Grafvollud, Ofnir, and Svafnir, the first two being the sons of Grafvitinir, who in addition to Níðhöggr all gnaw at the roots of the tree. The tree is mentioned frequently in the Grimmisal poem, the writing of which is attested to be from the perspective of the god Odin. The stanzas 31 to 35 read the following:

"31. Three roots on three roads. From under the ash of Yggdrasil; Hel lives under one, under another the frost giants. Human beings under a third. 32.Ratatosk is the name of the squirrel who shall run on the ash of Yggdrasil words of an eagle he shall carry down and say to Nidhoog below. 33. There are four harts who with necks bent back gnaw on the buds: Dain and Dvalin, Duneyr and Durathror. 34. Many snakes lie under the ash of Yggdrasil and may every witless person consider that; Goinn and Moinn- (they are the sons of Grafvitnir), Grabak and Gradvollud Ofnir and Svafnir, I think will ever. Eat the branches of the tree 35. The ash of Yggdrasil suffers difficulty, more then men may know; a hart bites from below, yet on the side it rots; Nidhogg harms it from below."

― Grimmisal