In the beginning there was nothing, there was only the yawning void, the great gap before all things. In the Great Gap she always was and always will be. The Great Cow Ambulhda, more massive than all things, so great mortals can never hold her in their minds.
Then Muspelheim came to be. The land of Fire and Light where only those born of flame can dewll. Surtr was there in its formation, Father of the Flame, his massive sword guarding the gates of Muspelheim forever and ever letting only those born of flame enter. Surtr will never leave the lands of Muspel, not until Ragnarok come and the moon dies and Surtr remakes the world in fire. Muspelheim was above the Gap between all things and its flames made a Haze of Heat that moved into the Great Gap.
Then Nifelheim came to be. The Land of Ice and Water where the Frost Giants make their home endlessly seeking to unmake all things returning them to the eternal cold. Laufey was there in its formation. His staff of black ice bringing forth the hordes of frost giants and with them the eternal frozen death. Nifelheim was below the Great Gap between all things and it's Frozen Waters made a Mist of Frost that moved into the Great Gap.
The Mist of Frost and the Haze of Heat met together in the Great Gap swirling and mixing unil waters of life dripped from their meeting. The First Drop was Yimir, the First of all Giants of Frost or Fire. Streching forth his left arm, reaching across the gap he conjured all the female giants into the gap. Streching forth his right arm he conjured all of the male giants into the gap. Streching forth his legs he conjured the last and most terrible of the Giants, the six headed son
They all lived and fed off of The Great Cow Ambulhda, her ever flowing utter making a river in the gap that gave life to all the giants. The Great Cow Ambulhda fed herself on the Black Stones of the Gap, the remnants of the time before time. Licking the black stones she brought forth the first of the Mortals, Buri the First.
Buri took to wife Gilda strongest and most cunning of the female giants. They begat Borr who took to wife Bestla a powerful mystic among the Giants. They had two Sons and a Daughter Ordin and Vough, and the daughter Villy. Together the three siblings plotted to make a world of their own. For the Gap was wide and vast with little to do or see.
So they plotted and schemed.
When they had crafted their weapons of power, trained in the arts of the warrior, and armored themselves with the shadows of the Great Gap they confronted Yimir, the first of the Giants.
It was not an easy feat but they slew Yimir his blood gushed forth in torrents unimaginable. They washed away many of the Giants, all those who had not fled to Muspelheim or Nifelheim. Buri and Gilda crafted a massive boat from the Black Stones of the Great Gap and used them to ride the blood tides.
From Yimirs Bones they made the mountains.
From Yimirs Flesh they made the earth.
From Yimirs Skull they made the sky.
From Yimirs Thoughts they made the clouds.
From Yimirs Organs they made the beats and monsters of the world.
Yimirs Blood flowed out around the earth and became the seas and waters of the world
And thus was the Land of Midgard made by the All-Father Odin and his siblings.