The World Tree: Yggdrasill

 The world tree, also known as Yggdrasill or Mimameidr in Old Norse, is a massive ash tree that supports the cosmos. Three of its roots reached Asgard, the abode of the gods, Jötunheim, the country of the giants, and Niflheim, the underworld. Three wells were located at the base of the tree: Urdarbrunnr (Well of Fate), from which the Norns (the Fates) watered the tree, Hvergelmir (Roaring Kettle), where Nidhogg, the monster that nibbled at the tree's roots, lived, and Mimir's Well (Source of Wisdom), for whose waters Odin sacrificed an eye. Despite being severely disturbed, the world tree was to be the source of fresh life after Ragnarök (Doomsday).

 Asgard

The sir, a group of gods that rule over Asgard and include Odin, Frigg, and Thor, reside there. The world is encircled by an unfinished wall, which is said to have been constructed by a stonemason who was actually a Hrimthurs and was killed by Thor once the gods discovered this. The immense dining hall known as Valhalla, or "hall of the slain," is also located in Asgard and is presided over by Odin. The dead prepare to assist Odin during the events of Ragnarök by joining the vast group of combatants known as "Einherjar" in Valhalla.

Álfheim/Ljósálfheimr

The word lfheim, which may be loosely translated as "Land of the Elves" or "Elfland," refers to the homeland of the Jósálfar light elves, who are subject to the Goddess Freya. There isn't much literature concerning lfheim, however, one poem refers to the elves as more "lovely than the sun."

Niðavellir/Svartálfaheimr

The Dwarfs, a race of skilled artisans who live underground and operate the mines and forges, inhabit Niavellir, which translates as "new moon" or "the waning of the moon." (Text connects the realm to the home of the dark/black elves.)

Midgard (Earth)

A race of people known as mankind live in the realm of Midgard, which is encompassed by an impenetrable ocean and the enormous sea serpent Jörmungandr. The Bifröst, a flaming rainbow bridge that leads to Himinbjörg, the home of the god Heimdallr, in heaven, is used by the gods of Asgard to go to Midgard.

Jötunheimr/Útgarðr

The Jötnar, the giants of Norse mythology, call Jötunheimr home. The Eddas depict the kingdom as having deep woods and high mountain peaks where winter never loosens its icy hold. At the Well of Misbrunnr, Odin gave up one eye in return for wisdom. This happened here in Jötunheimr.

Vanaheim

Vanaheim is the abode of the Vanir, a set of gods linked to fertility, knowledge, and the capacity for foresight. Little else is known about Vanaheim. The Vanir joined the Sir as a subgroup following the Sir-Vanir War. Consequently, people occasionally also refer to Vanir people as Sir people.

Niflheim

Niflheim, also known as "Mist World" or "Abode of Mist," is one of the earliest worlds to emerge from Ginnungagap in the Yggdrasil tree's origin myth. It is a realm of primordial frost. Only in Snorri's writings and in the Hrafnagaldr'ins does the word "Niflheim" appear.

Muspelheim

The first elemental planet to emerge from the primordial abyss of Ginnungagap was the kingdom of fire known as Muspelheim. Surtr, a jötunn giant who rules the globe and plays a significant role in Ragnarök's events, when the flames he delivers will consume Midgard, rules the universe.

Helheim

Helheim, also known as "Hel" or "The Realm of Hel," is the name of the deity "Hel" who rules over an underworld where many of the dead reside. This Norse afterlife is less a realm of perpetual happiness than it is a continuation of life elsewhere, in contrast to the Christian conception of damnation.