A great work of visual art, such as the mesmerizing black-and-white photograph that opens Wim Wenders' new documentary, The Salt of the Earth, has the power to draw you into its world, transfix, and perhaps eventually transform you. No wonder some viewers can stay for hours before the same work.

That's the effect produced by Brazilian photographer Sebastião Salgado's The Mines of Serra Pelada, a series of stills of a massive Brazilian gold mine 267 miles south of the mouth of the Amazon River. Carved down into the earth and into the side of the mountain, the mine, since abandoned, looks like the entrance to Dante's Inferno.

Blackened by mud, hundreds - perhaps thousands - of men climb like little ants up ramshackle wooden ladders with sacks of excavated dirt on their backs. Some stand on the dozens of little plateaus jutting all around the massive crater, while others rush back down the side under the watch of armed guards.

Wenders' film, an arresting exploration of Salgado's life and work, stays with its opening images for a few minutes, allowing viewers to take in first the overwhelming aesthetic beauty and next the biting social commentary captured in the photographs.

Narrated alternately by Wenders, Salgado, the photographer's wife, Lélia Wanick Salgado, and the couple's grown son, filmmaker Juliano Ribeiro Salgado, The Salt of the Earth follows the photographer's life from childhood to his training as an economist to his sudden decision to give up a lucrative career and devote his life to social documentary photography.

Salgado walks us through the more than half-dozen projects he mounted through his career, some lasting as long as a decade, to capture some aspect of the human condition - with an eye always to capture his subjects in their full social, economic, and political contexts. One major piece, Workers: Archaeology of the Industrial Age, captures the lives of the people around the globe who have made the world through their toil; others follow the tragic droughts, famines, wars, genocides, and forced mass migrations that have blighted the earth from Africa to the Balkans.

Wenders, no less a master of framing and cinematography than his subject, provides a majestic portrait that culminates with the founding by Salgado and his wife of the Instituto Terra, which has replanted a portion of the rain forest with great success.

The only flaw in The Salt of the Earth is its attempt to show so much. Every one of Salgado's stills gives occasion for long contemplation. Here, we are bombarded by hundreds. Some of the most brutal, gut-wrenching scenes of human suffering - from emaciated Ethiopian peasants and slaughtered Tutsi children to displaced Bosnians - are delivered in such rapid succession it becomes almost unbearable to keep watching.

Salgado's life and work, according to Wenders, has a definite arc. The projects that bear witness to human tragedy left Salgado morally exhausted and led him to despair for the fate of humanity. Having renounced his work for some time, Salgado returned to photography with a large project about the earth's natural beauty.

Salgado's stature as a great journalist and artist is surely secure. But one wonders about the conclusion Wenders draws from his career. Is the filmmaker implying that, like Salgado, the best we can hope for from a lifetime devoted to social justice is a spiritual breakdown? That it's better to turn away and commune with nature?

The Salt of the Earth **** (out of four stars)

Directed by Wim Wenders and Juliano Ribeiro Salgado. Distributed by Sony Pictures Classics.

Running time: 1 hour, 50 mins.

Parent's guide: No MPAA rating (shocking scenes of war, poverty and famine, violence, profanity, smoking).

Playing at: Ritz Five.