Ginnungagap
From the Voluspa section of the Norse-Icelandic Poetic Edda:

Of old was the age, when Ymir lived;
Sea nor cool waves, nor sand there were;
Earth had not been, nor heaven above,
But a yawning gap, and grass nowhere.

Ginnungagap is the abysmal gap of origin which forms the border between (ie, at once separates and joins) the northern ice and the southern fire. It is out of this gap through the action of the giants and gods that the world is born - middle earth (Miðgarð).

As with the Greeks, the mystery lies in the joint of what belongs below (ice, north, night, giants) with what belongs above (fire, south, day, gods). It is the nature of human being, the creatures of Miðgarð, to be subject to this mystery and to the care and anxiety which follow from its difficult complexity.