In the Piedmont hills of Italy there is a sanctuary underground. It is called Damunhur and consists of several levels and rooms. In fact, there are seven large halls. They are each lavishly decorated and were constructed by hand. To see them is to be awed by the art and architecture. Above all this however, one would only see a typical Italian countryside and nothing more.
This is how I imagine the underground communities that make up the world of Pa'Chot are constructed. Beneath the surface are connected cities and other structures but above the surface little is seen except the rocky and dusty surface of the planet.
That is what the Kevutian crew of the Constantia thought they had encountered until they found the underground community living below.