Yggdrasil is the Norse name of the World Tree, the cosmic tree that links three realms in Norse mythology. Said to be a gigantic ash tree, its name literally means “Ygg’s horse.”
Ygg, which means “terrible” or “dreadful,” is one of the names of the chief Norse god, Odin, who hung from the tree for nine days as a willing self-sacrifice to gain the wisdom of the runes.
Three roots support Yggdrasil’s mighty trunk. Each root passes through a different world so that Yggdrasil’s branches spread out over all worlds.
In one version of the myth, the three worlds are Asgard, home of the gods; Midgard, home of the humans; and Hel, the underworld. Another version of the myth describes the three roots as passing through Asgard; Jotenheim, the world of the frost giants; and Niflheim, the world of the dwarves.
Beneath one of the roots, usually mentioned in texts as the Asgard root, lies the sacred Urdarbrunnr, the well of fate. It is here that the three Norns, or Nornor, live. These are the three Fates of Norse mythology.
The Norns hold the destinies of all that live, and not even the gods have power over them. The Norns water the tree every day to keep its bark white and its leaves green.
Beneath the two other roots lie Mimisbrunnr, the well of wisdom, guarded by the giant Mimir, and the Hvergelmir, or roaring kettle, which is said to be the source of many of the Midgard rivers.
Near the Hvergelmir, the great serpent Nidhogg gnaws at one of Yggdrasil’s roots. An eagle sits in Yggdrasil’s branches, and between its eyes a falcon perches. The beat of the eagle’s powerful wings stirs the Midgard winds.
The goat Heidrun lives up there, too, and eats Yggdrasil’s leaves, while four stags, Dain, Duneyr, Durathror, and Dvalin, feed on Yggdrasil’s bark.
A squirrel, Ratatosk, scurries up and down Yggdrasil’s trunk. It carries messages back and forth between the eagle and the serpent Nidhogg.
The myths state that someday, when the final battle of Ragnarok arrives, Nidhogg will finish its gnawing and bring down Yggdrasil. Then Yggdrasil will then expire in flames set by the giants.