The Eye of Thios
Cathair is the largest City on the surface of Thios. In most respects it would be considered the Capitol, since it is the biggest trade city and receives thousands of pilgrims and immigrants each year. There is no formal government of Cathair. When decisions need to be made, representatives of each family meet in the arena surrounding the Eye of Thios to discuss and decide a course of action. It is then left up to the Executor of the city to enact the will of the families.
The city itself is wide, but no taller than six stories with the exception of the Arena, which is ten stories tall. Most of the buildings are made of a white stone common to the area and most of the roofs are covered by greenery of some sort. The roads are serpentine, but all of them will eventually connect to the Arena.