MidgardBelow Asgard was the Earth, or Midgard ("Middle World"), the defensive fortress which the gods build about the middle portion of the earth allotted to men in order to protect mankind from the giants. This was the world of humans. The Giants lived on this level, too. Some said their stronghold, Utgard, was in the barren mountains of Jotunheim far to the East. Others said that it lay across the vast Ocean that surrounded the Earth.
Midgard was surrounded by the Ocean. It was so wide that it was thought to be impossible for humans to cross. In the Ocean lurked the terrible World-Serpent, Jormungand. He was so big that his body circled Midgard and took his own tail in his mouth.
JotunheimThe homeland of the frost giants and rock giants. Situated in Midgard, on the middle level of the Norse universe, Jotunheim is separated from Asgard by the river Iving, which never freezes over. It lies in the snowy regions on the outermost shores of the ocean. Mimir's well of wisdom is in Jotunheim, beneath the Midgard root of the ash tree Yggdrasil.
Jotunheim is ruled by Thrym ("uproar"), the feared king of the frost giants. The stronghold of Utgard, the chief city of Jotunheim and the abode of the giants, is ruled by the giant Utgard-Loki. Other strongholds include Gastropnir, home of the giantess Menglad, and Thrymheim ("house of uproar"), mountain stronghold of the giant Thiazi.
Nidavellir and SvartalfheimTo the north of Midgard was Nidavellir. It was an area of caves and holes belonging to the Dwarfs. Nearby was Svartalfheim, where the dwarfs and the troublesome Dark Elves lived.