The Rwandan genocide occurred in 1994 when extremist Hutu groups, including the Interahamwe militia, began systematically killing Tutsi and moderate Hutus. Over the course of 100 days, an estimated 800,000 Rwandans were murdered in a government-led genocide. The violence was sparked by the death of Rwanda's president, a Hutu, in a plane crash that Hutu extremists blamed on the Tutsi. Centuries of ethnic tensions between the Hutu and Tutsi peoples, exacerbated by colonial influences, laid the groundwork for this tragic genocide.