In recent years, we are more and more witnessing the mainstreaming of radical ideas and nationalism in western liberal democracies. The Covid-Pandemic, climate change and the fight for equal rights – be it for LGBTIQ, Women or other marginalized groups – are only some examples which lead to high polarization, often (mis)used by different political groups. However, extreme ideas have increasingly moved from marginalization to the mainstream of modern societies. What structures and mechanisms lie behind this phenomenon? At the same time, the Western Balkans are still suffering from their difficult past of ethnic wars and nationalism which ultimately led to mass atrocities and genocide in the 1990s during the Yugoslav wars. Why are nationalism and radicalization so successful in Europe? What role do history and memory play in shaping narratives which lead to radicalization? How can genocide become possible and why are radicalization and nationalism a threat to democracy? Ultimately, what should be done to reverse these trends?