Rabbit City (Don't Lay it On Me, Man)

Rabbit City never was abandoned.  Not a lot of maps show the city, though it was the fifth largest in the region even before the rest of the cities emptied.  There is only one road that leads to the city, up a winding, narrow pass, and that one is in poor repair and half-choked with green briars for much of the year.  Rabbit City is built in a gentle valley surrounded by terraced farmland, self-sufficient, so far as anyone can tell; at least they have very little apparent access to the rest of the region or to the underground.  This remoteness undoubtedly contributed to its ability to remain inhabited and habitable without interruption.

Outsiders don't visit the city often.  It remains fairly isolated and remote, even to the lines of exploration made by those who would plunder or resettle the region.  There also seem to be times, related to the phases of the moon, where the city itself is especially difficult to reach, starting at the waning of the moon and culminating with the new moon where the city is apparently impossible to locate by any means.

Those who visit note that the population has dropped some from its apparent previous capacity, and there is talk of people having left.  Most visitors do not leave, however.  Almost anyone who spends significant time in Rabbit City eventually partners and has a family with a local, regardless of their prior feelings on relationships or other relationships they may have been in.  Couples who come to the city together seem to drift apart after a short time, taking up with locals instead.  Very few visitors return; those who do do not stay away from the city for long, and almost everyone who has spent time in Rabbit City seeks to eventually settle there.

Apparently the locals smell good.

The city was initially settled by the last group that those underground brought to the region, and while most of the residents of Rabbit City retain at least some features, culture, vocabulary and written language of their imported ancestors, they aren't significantly less diverse in feature and history than other folks from the region.  They do, however, share some features; ears that appear slightly pointed, significant freckling and raised birthmarks on the back that resemble scarring, and an apparently attractive scent.

We know that those underground were not shy about tinkering with the forms and features of animals they brought to the region, but only rarely did they extend that tinkering to the human form, and those cases were well-documented, subjects tended to be sterilized in the process, and the results were either very short-lived or disastrous.  Whether the apparent alterations to the people of Rabbit City are deliberate or occurred naturally is something we do not know, and it's largely an assumption based on a majority of the reports of explorers, as few natives of the city have gone to surrounding areas and those who do have not submitted to the kind of testing that would be necessary to determine if these stories have any basis in anatomy.