Cloudlands

The Cloudlands were a fabled kingdom in the sky, said to have once existed above the Stonelands.

History
According to Elminster's research, if the Cloudlands did in fact once exist then it would have been roughly 1,500 years prior to his writing of ecologies for the Stonelands and Goblin Marches.

Myths & Rumors
The legends claimed that one day the mage rulers of the Netheril cities of Asram and Anauria discovered the Cloudlands and sought to conquer them, believing they could act as a safehaven from the ever-expanding Anauroch desert. Their efforts ultimately destroyed the kingdom and the enchantments of its clouds, causing its cities and fortresses to fall and become the many large rock formations that dot the plains of the Stonelands.

Of those who believed in these legends, some thought that sky-dwelling creatures seen in the Stonelands might still be inhabiting its ruins. Others claimed that lingering spells from this fabled war are the cause of the area's frequent terrible storms.

Inhabitants
Legends said that the Cloudlands were home to asperii, cloud giants, giant eagles, mist dragons, pegasi, silver dragons, storm giants, and sylphs. They were also said to be home to a race of winged, elf-like beings, which may have been the Avariel. All of these creatures were said to have lived in harmony and only descended to the surface when they needed to gather or trade food or other necessities. They generally avoided nearby human kingdoms, especially Asram.

The giants in particular were said to frequently take stone from the surface, using it to build the Cloudlands' many cities and fortresses.