The course is an approximation to comparative studies on ethnic persecutions and genocides in the contemporary world. The first part of the course will focus on theoretical and conceptual reflection on the main global phenomena that the research considers have historically acted -and continue to act- as motives for ethnic persecution and genocidal acts: the State (-nation) and nationalism, racism, religion, or ethnicity. The analyzes and controversies around the typologies and character of mass crimes and about the concept of genocide crime will also be presented: constituent acts and elements, role of the State, typologies of perpetrators, motivations, contexts, local and international conditions, character of the victims. In the second part of the subject, the knowledge acquired will be applied to the analysis of some of the most studied cases and discussed by specialists in ethnic persecutions and genocides that occurred in various continents throughout the 20th century in order to acquire a comparative perspective . The main controversies and debates around these studied cases will be presented, including the Holocaust, the most documented and analyzed case of genocide. What is intended with the study of these terrible events is not to present a catalog of horror, but to analyze the how and why they occurred, suspecting the mechanisms, also institutional that can help to ensure that they are not repeated in the future.