At a U.N.-sponsored school, Guor Mading meets with pupils who are curious about his improbable story of escaping the horrors of war and becoming an Olympic runner. (Photograph provided by U.N. High Commissioner for Refugees)

At a U.N.-sponsored school, Guor Mading meets with pupils who are curious about his improbable story of escaping the horrors of war and becoming an Olympic runner. (Photograph provided by U.N. High Commissioner for Refugees)