What is "muspelheim"

In Norse mythology, Muspelheim , also called Muspell , is a realm of fire. This realm is one of the Nine Worlds, ruled by Surt with his consort Sinmara in some accounts. The denizens of Muspelheim were usually referred to as the Eldjötnar (or Eldthursar, Eldþursar — "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"; altn. Múspellmegir, Múspellsynir) 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:

The etymology of "Muspelheim" is uncertain, but may come from Mund-spilli, "world-destroyers", "wreck of the world".