At the centre of the nine worlds lies Midgard – the ‘middle enclosure’, the fenced homestead of humankind. Not a distant heaven of the gods, but the earth beneath our feet: built from the body of a slain giant and held together by a wall made of eyelashes. Of all the worlds it is the one we stand in.
The name is ancient and Germanic: Old Norse Miðgarðr, Old English middangeard, Old High German mittilgart, Gothic midjungards. ‘The enclosed region in the middle’ – ringed by the world-sea in which the Midgard Serpent Jörmungandr lies, its own tail in its mouth.
According to Snorri, Odin, Vili and Vé made the world from the body of the primal giant Ymir: from his flesh the earth, from his blood the sea, from his bones the mountains, from his skull the sky. And from his eyebrows (or eyelashes) they raised the wall that shields Midgard against the giant-world of Jötunheim. With Asgard, the citadel of the gods, Midgard is joined by the rainbow bridgeBifröst.
“Of Ymir's flesh was the earth created, / and of his blood the sea; / of his bones the hills, of his hair the trees, / and of his skull the heavens high.”Grímnismál 40, translation after Henry Adams Bellows (public domain)

Ymir & the making of the world · Jötunheim – land of the giants · The Midgard Serpent · The Nine Worlds · The Norse pantheon.
Snorri Sturluson, Gylfaginning (c. 1220). Grímnismál, Vafþrúðnismál (Poetic Edda), English public-domain translation: Henry Adams Bellows (1923). Wulfila Bible (4th c.), Beowulf. Scholarship: Rudolf Simek, Dictionary of Northern Mythology; John Lindow, Norse Mythology.