PARIS — Human migration is the story of our times. Victims of conflict and climate change, pushed by poverty at home and pulled toward opportunity abroad, people on the move are both a catalyst and consequence of globalization. Yes, immigration is a polarizing political issue, but also a keen reminder of the shared circumstances that bind us all.

As is often the case, the numbers and headlines and political declarations from all sides fail to tell the whole story. Photographs can help. They let us see what's at stake, and at play.

Reuters photographer Kim Kyung-Hoon caught this moment Sunday of a mother and her twin daughters fleeing tear gas near the U.S.-Mexico border wall. The 2014 World Press Photo of the Year was a much quieter image: John Stanmeyer's poignant shot that captured the paradox of our particular epoch in the migration saga, where technology can only go so far in connecting people to what they seek and who they love.

Aboard a rescue ship a year later in the Mediterranean, Francesco Zizola took what can be classified as a documentary portrait of several would-be immigrants, whose expressions of trauma and dignity recall the standard bearer of all such images: Migrant Mother by Dorothea Lange during her work surveying the internal migration caused by the Great Depression.

Migrant Mother — (© Dorothea Lange | OneShot)

As the ultimate victims of circumstance, it is often children who finally move our collective conscience — and certain images hold the power to shift the public debate over immigration. No one can unsee the images Nilufer Demir took of the corpse of Alan Kurdi, the three-year-old Syrian boy found dead on a Turkish beach in 2015, while John Moore's shot of a crying girl near the Mexico-U.S. border helped spark the outcry last spring over the American policy of separating migrant children from their parents.

The sad truth is that the vast majority of the suffering and stories go undocumented. Even sadder are those who disappear along the way without a trace, leaving behind loved ones back home with grief and uncertainty. Italian daily La Stampa reports on a new book by Cristina Cattaneo, a Milan professor of forensics and legal medicine, who has helped lead an effort for the past five years to document the identities of the estimated 30,000 would-be migrants who have died trying to cross the Mediterranean since 2001.

The vast majority of the suffering and stories go undocumented.

"Nobody ever thought to do for them what we do for ourselves," Cattaneo explained. "To give them an identity and give a response to the mothers, children, grandparents, to let them know if they should keep waiting or make their peace."

These 192 pages of text, entitled Naufraghi senza volto ("The Faceless Shipwrecked") help remind us of the real power of the photographs above: to tell the story of those who could not be seen.

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