In Norse mythology , Yggdrasil ( pron.: / ˈ ɪ ɡ d r ə s ɪ l / ; from Old Norse Yggdrasill , pronounced [ˈyɡːˌdrasilː] ) is an immense tree that is central in Norse cosmology , in connection to which the nine worlds exist. Yggdrasil is attested in the Poetic Edda , compiled in the 13th century from earlier traditional sources, and the Prose Edda , written in the 13th century by Snorri Sturluson . In both sources, Yggdrasil is an immense ash tree that is central and considered very holy. The gods go to Yggdrasil daily to assemble at their things . The branches of Yggdrasil extend far into the heavens, and the tree is supported by three roots that extend far away into other locations; one to the well Urðarbrunnr in the heavens, one to the spring Hvergelmir , and another to the well Mímisbrunnr . Creatures live within Yggdrasil, including the wyrm (dragon) Níðhöggr , an unnamed eagle , and the stags Dáinn, Dvalinn, Duneyrr and Duraþrór . Conflicting scholarly theories have been p...