A Serbian graffito from the mid-90s, seen on a Belgrade wall, with some relevance to today's Russian-Ukrainian situation ...

"Separatists of the world, Unite!"

Image [evidently outdated] from Wikipedia, with caption: Map of active separatist movements in Europe [Wikipedia notes that the link to this map has "multiple issues.]. Red names indicate regions with movements that only claim greater autonomy within the actual state. Black names indicate regions with important secessionist movements, although both categories include moderate movements. The nations highlighted in colors are the territories claimed by the local nationalist groups, including areas out of the state's borders and cases of annexation to other states.