Nordic mythology has a beginning and an end. The worshipping of nature forms a great part of the old ways, and the noticed natural cyclical repeating of events led to a conclusion that even the development of worlds concludes and starts over at one point in future. Even the destiny of the Gods is already shaped and known - it is called Ragnarok.

In the beginning, there were two primal elements - ice in a place called Niflheim, and fire, within the world of Muspellheim. These elements were separated by an enormous Yawning Void (Ginnunga Gap). But, when a spark from Muspell accidentally met the ice-drop of Niflheim inside the Ginnunga Gap, their combined powers created the first manlike form. It was called Ymir. The sweat from under his hands and feet grew a man and a woman, who were the ancestors of the Giants' race.
Ymir was nourished by the primal cow, Audumla. She herself used to feed herself by licking an ice-block, until she revealed the shape of a man - it was Buri, from whom the Aesir family descends. His son Bor with his wife Bestla is the parent of Odin, Vili and Ve - a trinity which might represent three different aspects of Odin. The three of them slew Ymir, and the whole race of Giants drowned in his blood, all but Bergelmir and his woman - this is how the race of the foes of the Gods is, later on, renewed.
Odin, Vili and Ve placed Ymir's grand body in the very middle of the Yawning Void and created earth of him. His blood was used for making the waters, his flesh for the land, his bones were turned to crags, his teeth to stones, and his hair to trees. The brows of Ymir are a citadel which surrounds the middle of this space - Midgard. His skull is what heaven is made of. Four dwarves by the names of East, West, North and South are holding it. The clouds are Ymir's brain. At the north end of heaven giant Hraesvelgr, with the plumes of an eagle, stretches for a flight every now and then, causing the wind rising from under his wings.
When the trio created the world, they decided to shape two trees in the form of men, and then they filled them with gifts of spirit, life, feeling, senses and speech. Their names were Ask and Embla, after the trees they were made of (ash and elm).
Odin, Vili and Ve created the world called Asgard for them. At one border of this world, there is a hall with high-throne, Hlidskjalf, from which Odin can see absolutely everything throughout the worlds.
The race of Aesir had begun with Odin. His first born son is Thor, whom he had had with Earth. Thor, along with the children of Odin and his wife Frigg forms the first generation of Aesir, the so-called Elder Asgard.
Night is daughter of a Giant called Narfi. One of her children, probably with Odin, is Day. Night and Day ride around the earth on the horses, given to them by Odin, every two half-days.
Sun and Moon were lifted to the sky as the result of the gods' anger towards their father - a human, Mundilfari - who dared to insult the Aesir by giving his children such high names. Now they are illuminating earth, and they are forced to do so, because behind them are running two gigantic wolves trying to swallow them.