Yggdrasil

aka The World Tree

According to Nordic legend, it connects the three worlds: Gladsheim (or Asgard), Midgard (or Earth), and Niflheim (or Hell). Its roots are deeply embedded in Niflheim, while its trunk soars through Midgard, and its branches hold up Gladsheim.

Yggdrasil is analogous to Marduk's spear and the Tower of Babel in the sense that it holds the firmament down, and if it is destroyed, we can kiss this world goodbye.

It is far to the north (possibly on or near the pole), and is protected by Tviblindi and his berserkers.