Snorri's Edda, Gylfaginning 15-16: "Where is the chief abode or holy place of the gods?" Hárr answered: 'That is at the Ash of Yggdrasill; there the gods must give judgment everyday.  ...The Ash is greatest of all trees and best: its limbs spread out over all the world and stand above heaven. Three roots of the tree uphold it and stand exceeding broad: one is among the Æsir; another among the Rime-Giants, in that place where aforetime was the Yawning Void; the third stands over Niflheim, and under that root is Hvergelmir, and Nídhöggr gnaws the root from below...  Much is to be told of it. An eagle sits in the limbs of the Ash, and he has understanding of many a thing; and between his eyes sits the hawk that is called Vedrfölnir. The squirrel called Ratatöskr runs up and down the length of the Ash, bearing envious words between the eagle and Nídhöggr; and four harts run in the limbs of the Ash and bite the leaves. They are called thus: Dáinn, Dvalinn, Duneyrr, Durathrór. Moreover, so many serpents are in Hvergelmir with Nídhöggr, that no tongue can tell them."