Calysto (Planet)
The planet Calysto is a young world where native life had evolved, but no sentient creatures had evolved, yet. With the help of the NorAellians, they tamed the world and have turned it into an idealized planet over the last 700 years.
An interesting feature of Calysto is that while all cities have above ground buildings, public parks, restaurants, etc, most of their residential structure (and supporting commercial structure) is underground. This is done to keep from urbanizing the planet too much; the urbanizing has been done underground to a degree not done on other worlds.
One reason for this was the original colonists had spent most of their lives living either in a habitat, or on a ship. They were more comfortable being enclosed than being in the open air, but they also couldn't deny the natural beauty of the planet.
TBD.