The arces of Lyn-Srial

There are four floating citadels of the flying beings known as the Lyn-Srial. These citadels are called arces (pronounced: ark'əs), each is an arx.
There are two arces in the northern hemisphere and two in the southern. They float, hidden in the clouds and obscured by magic. They comprise the beating religious heart of the Lyn-Srial body politic. They also house a sizable defense force.
The four arces are:

• Arx Nolatha - The primary religious center. The formal receiving place for visits by the Gods of the Pantheon of Light
• Arx Cosa - The headquarters of the Lyn-Srial military
• Arx Niunithal - A necropolis of the most celebrated dead
• Arx Rotons - A multipurpose Arx and location of their most secure prison

Architecture

Each arx is constructed on an inverted pyramid. Using the power collected by that construction, they reverse gravity and float in the sky among the clouds. The effect on gravity is such that below the base of the pyramid, one can walk upside down on (and in) the upside down pyramid with the earth in the sky "above." This effect extends only about three meters into the sky around the pyramid. Because of this effect, and without the cleaning mechanism of rain, the surface of the pyramid tends to accrue moisture and debris and is a fertile surface for mosses, molds and lichens. Even some shade-loving plants and epiphytes can be found on the underside of the arces.
Only when one crosses the base of the pyramid onto the structures above does gravity revert to normal.
The arcane power collected by the pyramids also provides for a continuous enhanced arcane ritual of obscuration.