This chapter explores the genocidal intersection between political history and ethnographic geography in European or near-European regions where the traditional continental empires met the emerging hegemony of Western nation-states. In particular it considers how and why the introduction of nationalism proved toxic in these multicultural ‘rimlands’, with Macedonia and Thrace as illustrative examples. Here the wartime shattering of empires (1912-1948) and their succession by fiercely nationalist competitors resulted in repeated spasms of extreme zero-sum violence whose key outcome was the ‘unmixing of peoples’ by mass deportation, and/or annihilation.