She survived Rwanda’s 1994 genocide. Now she promotes peace through education.

When Theoneste Mutabazi started teaching at Umuco Mwiza School in Kigali in 2008, he marveled at everything its students had. There was an art room, a music room, and a library “with many books,” he says during a phone call from his office in the Rwandan capital. Since then, Umuco Mwiza, whose name means “good culture” in the Kinyarwanda language, has added more classrooms and even a large recreation area.

Mr. Mutabazi, who is now the school’s principal, notes in an excited voice that “Our children play soccer on the big playground on Friday afternoons.” They also are very happy to attend athletic meets, concerts, and field trips, he says.

All of this is possible thanks to a woman living half a world away.