In the beginning there was no heaven or earth, only bottomless nothing surrounded by mist. There was a fountain that flowed into 12 rivers in the middle of this nothing. Each river froze as it travelled further from its source. To the south of the mist, there was light, from which a warm breeze came and melted the ice of the 12 rivers. Clouds were formed from the meeting of the warm air and the cold. The clouds turned into the frost giant Ymir and his cow, Audhumbla. Audhumbla's milk fed the giant. As the ice melted, the cow licked it and salt was exposed. One day she licked through to a point where a man was visible in the ice. On the first day, his hair was visible, on the second his head and shoulders, on the third he was released from the ice and became the first god, the father of Odin, Vili and Ve.
The three young gods slew the frost giant and his blood formed the seas. His bones became mountains and his flesh became earth. From his hair, plants grew. There was Aske the ash tree and Embla the elm. The ash tree became the basis for a man and the elm tree became the basis for a woman. Odin gave the man and woman life and a soul each. The couple were given reason and motion, and speech and motion from Vili and Ve respectively.
Odin was responsible for separating darkness from light, creating night and day. Odin created Midgard (Middle Earth) for humans to live in, as well as Asgard for the gods. The universe is propped up by Yggdrasil the ash tree. One of the tree's roots touches Midgard, another touches Asgard and another rests underground which is the place where dead souls go, run by Odin's sister, Hel.
Ymir was not entirely slaughtered; there is a part of his body that still survives and sleeps at the base of Yggdrasil. His stirring body is the cause of earthquakes.