 In Norse mythology , Bifröst ( / <unk> / or sometimes Bilröst or <unk> ) is a burning rainbow bridge that reaches between Midgard ( the world ) 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 , and 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 alternately refer to the bridge as <unk> ( Old Norse " Æsir 's bridge " ) . 
