Note: initial content copied from Wikipedia:City of Thi.
Thi is in a relatively unexplored area of Oz. The fields surrounding it tend to shift, turning a traveler in the opposite direction. Surrounding Thi is a huge field of prickly thistles. Beyond the thistle field is an illusory wall surrounding the city.
The inhabitants of the city of Thi are called Thists. They have diamond shaped heads and heart shaped bodies. Their stomachs and throats are lined with gold allowing them to eat the thistles that grow around their city.
Since the City of Thi is within the borders of the country of Oz, it is under the jurisdiction of Ozma. However, being so isolated, the citizens of Thi know nothing of her. They believe themselves to have no king but in reality their king is the High Coco-Lorum, a public servant who solves civil disputes by making up laws. The people are unaware of his leadership and content in their ignorance, and he is able to get them to do whatever he wants.