Salgado:An Uncertain Grace

From a Brazilian mine where 50,000 mud-covered men haul heavy sacks of dirt up and down slippery ladders in search of a stray nugget of gold, to a former lake in western Africa now swallowed by the encroaching desert, where emaciated, starving people walk over its surface of sand, photographer Sebastião Salgado explores the lives of the world's often-ignored people with a critical eye and an empathetic heart.