Excerpted from The World of the Wilderlands of High Adventure:
The second-most important of the celestial bodies, before even the moons and the planets, is the great planetary ring known as Heaven’s Bridge; to followers of Odin, Thor, and other gods of the Valonar Pantheon it is known as Bifröst, the Rainbow Bridge, and it is said that many of the gods use the bridge to walk between the worlds. This ring appears to viewers as a curving band across the sky, a finger-wide glittering road crossing from horizon to horizon, high above the moons. From the Wilderlands proper, it is visible in the southern skies. It is visible day and night — by day it appears a shimmering blue with a twinkling of other colors flaring here and there, and at night it dances with all the colors of the rainbow. The entire ring turns a deep gold, even by day, once every 52 years, an event that is met with wonder and horror, depending on the circumstances and superstitions of the viewer. The cycles of the ring are used by many cultures as a means to mark the passing of cycles and ages. Heaven’s Bridge last shimmered gold
10 years ago, in 4423 BCCC (5050 in the Takvim calendar), and will do so once again in 4475 BCCC (5102 Takvim).
Gods particularly associated with Heaven’s Bridge include Anubis, Brighid, Hathor, Heimdall, Nephtlys, Shang-Ta, and Yog. None are said to possess the Bridge; they are said to guard it or to be the guide across it, but never possess it.