Dark Lake Ziggurat

The Dark lake Ziggurat was a structure with many ancient builders that stood in Underdark caverns on multiple planes, warping reality in its vicinity.

The Dark Lake Ziggurat contained many chambers, each of which lies on a different plane of existence. A traveler could use the ziggurat to travel to other planes; however, most creatures that tried were ensnared in the reality dysfunction that beat at the ziggurat's heart.