Yggdrasil

Yggdrasil is a central sacred tree in the beliefs of Norse mythology.

It is the tree upon which the Nine Realms of the Norse mythos rests upon and of which one of three roots sprawl down into the Well called Mímisbrunnr, guarded by Mimir and lying in the lands of the jǫtunn, another root sprawls into the lands of the æsir and into the Urðarbrunnr, where the nornir gather water to give to the tree. The last and final root goes through the realm of the unworthy dead and into the Hvergelmir, which holds numerous snakes and the great wyrm Níðhöggr. These roots are regularly gnawed upon by Níðhöggr, which causes great strife and evil in the world, and whom will rise out from the tree and out of the realm of Niflheimr with all of the unworthy dead upon his wings once Ragnarökr begins.