In Norse mythology, Muspelheim (Old Norse: Múspellsheimr), also called Muspell (Old Norse: Múspell), is a realm of fire. This realm is one of the Nine Worlds, ruled by Surtr with his consort Sinmara in some accounts. The denizens of Muspelheim were usually referred to as the Eldjötnar ("fire giants") in Norse tradition, though they were also identified by other epithets in Eddic poetry, such as the Múspellssynir (or Múspellsmegir — "sons of Muspell") and the Rjúfendr (from rjúfa — "to break, tear asunder", Destroyers of Doomsday). Both of these terms sometimes described an entirely separate mythological species that dwelled alongside or in place of the eldjötnar within this fiery realm. Muspelheim is fire; and the land to the North, Niflheim, is ice. The two mixed and created water from the melting ice in Ginnungagap. The sun and the stars originate from Muspelheim.
According to the Ragnarök prophecies in Snorri Sturluson's Gylfaginning, the first part of his Prose Edda, the sons of Muspell will break the Bifröst bridge, signaling the end of times:
Muspelheim
[Gudaskymning]
[From the south comes the forces of chaos and destruction. The ultimate heat from the world of Muspel will very soon burn the world and turn it into ashes. The firegiant Surt rides with his hords to meet the gods in the final battle of Ragnarok. But the whell of fate will turn once again and from the ash a new world will rise.]
Kaun
Gudaskymning faller på glöden
börjar flamma (Ur) ödets eld i Muspelheim
Ragnarök härstamma.
Muspilli flammor över Jord,
snart kommer Surt att härja,
Jättarna tända Ragnarök
(och) runor av eld besvärja.
Muspel öppnat sig
Surt som i syd med draget svärd
kallar på Muspels söner,
kommer till kamp på Vigrid slätt,
då hjälper inga böner.
Från syd kommer kaos.
Makter av eld här stormar fram
nu skola världen brinna.
Jättarna dräper guden Frej då
kommer ödets timma.