Midgard

Midgard ("The Middle Home" or "Middle Dwelling") was the world of men. It was surrounded by a mountain-wall called Midgard-wall, made out of Ymir's eye-brows, to protect the men from the giants.

In the Poetic Edda, the wall is called Midgard, not the land.
"Mithgarth the gods | from his eyebrows made,
And set for the sons of men;
And out of his brain | the baleful clouds
They made to move on high."
(Grímnismál)

Midgard was one of the nine worlds, connected by Ygdrasil, it was located in the middle level.

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