Bifröst

thumb|The god Heimdallr stands before the rainbow bridge while blowing his horn (1905) by [[Emil Doepler.]] In Norse mythology, Bifröst (; modern Icelandic: Bifröst; from Old Norse: ), also called Bilröst and often anglicized as Bifrost, is a burning bridge that reaches between Midgard (Earth) and Asgard, the realm of the gods. The bridge is attested as Bilröst in the Poetic Edda, compiled in the 13th century from earlier traditional sources; as Bifröst in the Prose Edda, written in the 13th century by Snorri Sturluson; and in the poetry of skalds. Both the Poetic Edda and the Prose Edda also refer to the bridge as Ásbrú (Old Norse "Æsir's bridge").

According to the Prose Edda, the bridge ends in heaven at Himinbjörg, the residence of the god Heimdall, who guards it from the jötnar. The bridge's destruction during Ragnarök by the forces of Muspell is foretold. Scholars have proposed that the bridge may have originally represented the Milky Way and have noted parallels between the bridge and another bridge in Norse mythology, Gjallarbrú. It may also represent other phenomena, such as the Aurora Borealis, which fits better with the notions of it being fiery and having three colours, while a rainbow form is very distinct and well-known, being stable and not fiery, with more numerous colours always in the same order. Also, rainbows do not end in the heavens, but appear to arch back and return to the land.