D&D 5th: Demon Tower of Madness
The Plaguewrought Land (also called the Plaguewrought Lands) is the name given to what was once the state of Halruaa, a large area south of Chondalwood that continues, as of 1479 DR, to be wracked by the effects of the Spellplague. Inside this plagueland the ground heaves like waves on the ocean and pieces of land levitate randomly to form earthmotes. The vegetation that grows here is strange and twisted and may sprout, mature and then die in a matter of minutes. Most people who travel into this region are killed very quickly by the wild magic.
The border has been more or less stable for nearly a hundred years. Pilgrims, encouraged by the Order of Blue Flame, often travel to the Plaguewrought Land in the hopes of acquiring a spellscar.