Yggdrasil

In Norse mythology, Yggdrasil (pronounced /ˈɪɡdrəsɪl/; from Old Norse Yggdrasill, pronounced [ˈyɡːˌdrasilː]) is an immense tree that is central in Norse cosmology; the world tree, and around the tree exist nine worlds. It is generally considered to mean "Ygg's (Odin's) horse".
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 hold their courts. 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.