7. Rwanda (1994)
The 1994 genocide in Rwanda led to the rapid collapse of state authority, resulting in the systematic killing of over one million people, primarily Tutsi, in less than three months. The aftermath necessitated extensive international intervention, including the establishment of the International Criminal Tribunal for Rwanda (ICTR) to prosecute perpetrators and the implementation of the Gacaca court system for community-based justice. These efforts underscore the critical importance of timely and decisive international action to prevent and address such crises (un.org).