Visage
"This is the port of Visage, where faces may not be naked. Except one: a stone monument the size of a village church, serenely gazing upwards. Flourishing-of-Years."

Visage is an island in the southern Unterzee whose main feature is a large face that watches the sky. Everyone on the island wears masks, according to their role. For example, those that wish to trade wear locust masks, those who wish to learn of Visage wear frog masks, and spies wear bat masks. Once a mask is chosen, its wearer must play their assigned part.
It is implied that there are little to no permanent citizens of Visage, only an endless stream of people playing them, possibly for years at a time, before giving their positions to others.
Some notable locations include the Flood Court, which is always flooded to a certain degree. Said degree varies - the water could be ten feet deep, but it could also be up to one's ankles. There is also the Library of Parts, where citizens go to learn how to perform what their mask asks of them.
Visage's face is hollow, and it is possible to enter its interior through its ear. This is done on festival days. During the festival, in complete darkness, people remove their masks and trade secrets, though nobody knows whose secrets are whose. Trading masks, however, is completely unheard of.