Catalonia's push for independence from Spain seized headlines this month, capturing international attention as a potentially successful separatist push within the relatively stable confines of Western Europe. Catalonia's secession would raise a whole host of questions for a range of international bodies — most notably, the European Union — that they'd prefer to ignore.
Why it matters: There are separatist movements all around the globe — even in most U.S. states — but the world tends to focus on those that have the potential to upend our understanding of the world and reshape geopolitics as we know it.