Twenty years ago, a plane carrying Rwanda’s president was shot down over Kigali. To this day we don’t know for sure who did it, but the incident nevertheless sparked 100 days of brutal killings across the “land of a thousand hills.”

In the end, the genocide claimed 800,000 lives. But how do you begin to wrap your head around a number like that? One way is to see on a map just how many mass graves are dotted across the entire country. Yale’s genocide studies program provides a before and after satellite view of Rwanda. Click on each map to see a larger version.

Another way is to hear stories from the people themselves. Genocide Archive Rwanda has compiled a google map annotated with oral history and court testimony from a number of sources, both within the borders and outside of them. Watch as Murebwayire Josephine recounts how she held hands with her daughter during a mass execution, barely surviving herself.

Read Canadian Geographic’s feature story about a Canadian immigrant who returns to Rwanda 20 years after escaping the 1994 genocide.