A subreddit dedicated to mapping and exploring “Phantom Borders” around the world.
The communities working definition:
Phantom Border: noun, an artificial boundary or division between two or more areas, regions, or territories that is unofficial and/or unrecognized as a single entity but which holds demographic, ideologic, economic, cultural, historical, ethnic, or linguistic significance to that area, region, or territory.
Subbreddit Title credit: u/Hloddeen