Bifröst

In Norse mythology, Bifröst (/ˈbɪvrɒst/ ⓘ[1]), also called Bilröst, is a burning rainbow bridge that reaches between Midgard (Earth) and Asgard, the realm of the gods.

[5] Later in Grímnismál, Grímnir notes that Asbrú "burns all with flames" and that, every day, the god Thor wades through the waters of Körmt and Örmt and the two Kerlaugar: In Fáfnismál, the dying wyrm Fafnir tells the hero Sigurd that, during the events of Ragnarök, bearing spears, gods will meet at Óskópnir.

In chapter 13 of Gylfaginning, Gangleri (King Gylfi in disguise) asks the enthroned figure of High what way exists between heaven and earth.

Laughing, High replies that the question isn't an intelligent one, and goes on to explain that the gods built a bridge from heaven and earth.

High says that the bridge consists of three colors, has great strength, "and is built with art and skill to a greater extent than other constructions.

"[9] High notes that, although the bridge is strong, it will break when "Muspell's lads" attempt to cross it, and their horses will have to make do with swimming over "great rivers."

High responds that the gods do not deserve blame for the breaking of the bridge, for "there is nothing in this world that will be secure when Muspell's sons attack.

[18] In J. R. R. Tolkien's legendarium, the "level bridge" of "The Fall of Númenor", an early version of the Akallabeth, recalls Bifröst.

In the Marvel Cinematic Universe film Thor, Jane Foster describes the Bifröst as an Einstein–Rosen bridge, which functions as a means of transportation across space in a short period of time.