(1964) mentions it in passing with a reference to Heimdall and Loki, but no duration is given. This implies that the bifrost is only as long as it needs to be. As an aside, the distance between Asgard Peak and Midgard Peak in Canada is 1.4 miles. It's not even close, Odin. The Rainbow Bridge (reinboburitsuzi, Reinbo Burijji) is a suspension bridge in Minato, Tokyo, Japan, that connects Shibaura Pier to the Odaiba waterfront development. Kawasaki Heavy Industries built it, with work beginning in 1987 and finishing in 1993.