Yggdrasil

In Norse mythology, Yggdrasil (Old Norse Yggdrasill, IPA: [ˈyɡˌdrasilː]; the extra -l is a nominative case marker) is the World Tree, a great ash tree located at the center of the universe and joining the nine worlds of Norse cosmology. The trunk of the tree may be thought of as forming a vertical axis around which these worlds are situated, with Ásgard, realm of the gods, at the top and the Hel, located in Niflheim, at the bottom. Midgard, our world that is inhabited by humans, is located in the middle and surrounded by Jötunheim, land of Jötunn, both of which are separated by the ocean. Yggdrasil is also sometimes referred to as Mimameid or Laerad.