Sky continent

A sky continent, also called a skycon, aerial continent, or aercon, is a massive artificial structure that resides in a planet's atmosphere, ranging in size from a large city to a mountain range or larger.

Purpose
Sky continents are built for various reasons, most commonly to ease crowding issues on planets covered in cityscape. They are also a standard feature on inhabited gas giants, as well as terrestrial planets whose surfaces are too hostile to support life.

Structure
These monstrosities typically come in two flavors: a solid shell filled with city, or a platform upon (or beneath) which city is built. The framework is made from lightweight metamaterials, some of which actively repel gravity or otherwise ease the burden on the primary antigravity systems.

Notable instances
Riesel plays host to many sky continents, including the infamous Hascu Village.