KAMPALA, Uganda — In the packed aisles of this city’s largest market, every passageway is choked with people, but none of them are old. At an elementary school graduation, hundreds pack the audience, but no grandparents appear to be among them. Even in the pharmacies and optical shops up and down this 1.8-million-person capital’s clamorous downtown, the faces are entirely young.

Follow the frenetic streets of Uganda’s cities to the web of dirt roads pockmarked by craters and bordered by banana trees, though, and thousands of villages await, each a smattering of huts of mud and houses of crumbling cement, seas of red soil splashing with walls of green vegetation, and churches beneath humble steeples or even humbler roofs of corrugated aluminum.

In each of them, Africa’s aging revolution c

See Full Page