The Buried City (水葬都市, Suiso Toshi, Burial City) is accessible through the formerly blocked dark passage in the Sunken City.
The Buried City is a rather deep world filled with many scattered buildings, some of them decorated by strange drawings of weird mounds or odd quadrupedal creatures. Given that equipping the Penguin effect causes Urotsuki to swim indefinitely, much like in Atlantis and the Star Ocean, this area is apparently submerged deep underwater.
Between the buildings are many NPC's - men, women, women with babies, old women and single babies. None of them can be interacted with, except single babies, which produce short baby's cries when interacted with. Urotsuki can kill all of the NPCs in this area except for the lone babies. If you equip the Glasses effect, all NPCs here will become grave crosses.
By going into the building with a door in it and another drawing of a strange quadrupedal creature, it will lead you to the Chaos Exhibition. There is also a pink UFO-like object southwest from this building, and when Urotsuki interacts with it, she will get in and will be propelled back up to the Sunken City's entrance.