These tales have existed for thousands of years in the form of poems, songs and stories until put into written form in the early 11th century. Though several authors attempted to preserve them our “best” source is Snorri Sturluson’s Prose Edda. This is the creation story. This is the first of the 32+ Norse Myths. My main source is the “The Norse Myths” by Kevin Crossley-Holland.
In Norse mythology, Bifrost is the bridge between Midgard, the realm of man, and Asgard, the realm of the gods. Since it is the only way for the giants to enter Asgard it is closely guarded by Heimdall, the watchman of the gods.
Bifrost was made of three colors with magic and great skill by the Aesir and is incredibly strong. It is also called Asbru, referring to its makers. At the end of the cosmos, this rainbow-bridge will collapse.
In Myth 14, The Lay of Thrym, it is Heimdall’s idea to Dress up Thor as a woman, in order to trick Thrym, the king of the frost giants, into thinking it was Freyja. The ploy works and Thor recovers his stolen hammer Mjollnir.
Heimdall was associated with the sea and was the son of nine maidens (9 waves??). In Myth 5 – The Song of Rig he calls himself Rig and travels across the land visiting several households, speaking honeyed words, winning over the woman of the household and creating the three races of men.
His acute senses make him an ideal watchman for the gods. His hall is Himinbjorg (Cliffs of Heaven) which stands near the rainbow Bifrost. He owns the horn Gjall which can be heard throughout the nine worlds.
He needs less sleep than a bird and can see a hundred leagues in front of him as well by night as by day. He can hear the grass growing on the earth and the wool on sheep, and everything that makes more noise – Snorri Sturluson