Omo valley, Ethiopia
Surma boys in the lower Omo valley in south-west Ethiopia, which is home to eight different tribes, numbering about 200,000 including the Surma.
A huge hydroelectric dam on the Omo river is being built.
It threatens to destroy a fragile environment and the livelihoods of tribes that rely on the river and its annual flood.
Photograph: Una foto una sonrisa/Survival International