From left: Sekou Sheriff, of Barkedu village in Liberia, whose parents died at an Ebola treatment center; a polio vaccination booth in Pakistan; a schoolgirl in Ethiopia examines underwear with a pocket for a menstrual pad; an image from a video on the ethics of selfies; Consolata Agunga goes door-to-door as a community health worker in her village in Kenya.

From left: Sekou Sheriff, of Barkedu village in Liberia, whose parents died at an Ebola treatment center; a polio vaccination booth in Pakistan; a schoolgirl in Ethiopia examines underwear with a pocket for a menstrual pad; an image from a video on the ethics of selfies; Consolata Agunga goes door-to-door as a community health worker in her village in Kenya.