The ancient universe is visualized as nine worlds divided up into three sets of three on three end or no beginning, sustained by the Nornir known as Urðr, Verðandi and Skuld. They would pour water over the branches so that the tree would not rot.
At the top perched a great eagle with a hawk resting between its eyes. The serpent Nídhögg gnaws at the roots. Ratatosk, the squirrel, runs up and down the trunk carrying insults from the serpent to the eagle.