On April 6, 1994, Rwandan President Habyarimana, a Hutu, was killed when his plane was shot down. The attack sparked immediate and horrific violence across the country, nearly decimating the minority Tutsi population.

Before the genocide, about 85 percent of Rwanda's 7-million-person population was Hutu, about 14 percent were Tutsi, and the final 1 percent were Twa. The Tutsi minority had formerly ruled the country, and when Habyarimana died, Hutu extremists began systematically killing Tutsi, announcing calls to massacre via radio broadcasts.

A genocide memorial made of victims' bones is on view at a church just outside the Rwandan capital Kigali. The church acted as a refuge for some 5,000 women and children during the massacres. | (REUTERS/Finbarr O'Reilly)

In the weeks following the April 6 plane crash, 800,000 Tutsi died. Thousands of Hutu were also killed trying to protect Tutsi neighbors, or otherwise opposing the killing sprees.

A Tutsi-dominated rebel group, the Rwanda Patriotic Front, eventually quelled the killings and instated President Paul Kagame — along with a fragile peace. But the country's dark legacy has not been forgotten.

"It was a big lesson for all of us," Florence Bugemimana, a Rwandan born a year after the killings, told The Guardian. "The whole country. Everyone suffered. No one wants that again."

In remembrance of this weekend's somber anniversary, here is a selection of photos from that horrific summer, and the unstable few years following.

May 30, 1994: Children hide in a house near their orphanage, which was hit by shelling. | (REUTERS/Corinne Dufka)

July 28, 1994: A woman collapses with her baby alongside the road connecting the Kibumba refugee camp and Goma, a city in Zaire, which as of 1997 became known as the Democratic Republic of the Congo. | (REUTERS/Ulli Michel)

August 21, 1994: A Hutu girl sits tensely within a crowd of some 10,000 Rwandan refugees, who were stopped from crossing into Zaire after the border was closed while French troops patrol the area. | (REUTERS/Corinne Dufka)

July 20, 1994: A Rwandan refugee stares at a mass grave. Refugees who escaped the fighting faced death from dehydration, lack of food, and cholera. | (REUTERS/Corinne Dufka)

Nov. 11, 1996: A woman checks her friend's hair for insects at a refugee camp near Giseny, Rwanda. | (REUTERS/Peter Andrews)

Jan. 1, 1996: Close to a million refugees make their way back from Zaire to Rwanda. | (REUTERS/Peter Andrews)

Nov. 17, 1996: A Hutu refugee helps her daughter with an IV at a local hospital in Goma. | (REUTERS/John Parkin)

Nov. 18, 1996: Refugee children who became separated from their parents look out from the back of a Red Cross truck. | (REUTERS/Corinne Dufka)