Yggdrasil the giant ash tree supporting the universe. It is closely related to the tree of life, a motif found across many cultures, and the tree of knowledge, which was said to grow in the Garden of Eden in Abrahamic religions. In Norse mythology, Yggdrasil is an enormous ash tree that connects the nine worlds, including the underworld (Niflheim), the earth (Midgard), and the realm of the gods (Asgard). It is associated with both life and death : it acts as a gallows that the god Odin hangs himself from in order to gain mystic knowledge, and it is said to be the source of new life after Ragnarök (Doomsday), the catastrophic final war of the gods.