Photojournalist David Wallace walks with a woman looking for the remains of her older brother in Arizona’s Organ Pipe Cactus National Monument, one of the harshest and most remote places along the nearly 2,000-mile U.S.-Mexico border.

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This episode was recorded, edited and produced by Hannah Gaber, with field interviews and sound from David Wallace. Kaila White was our production manager. Our technical director was Nate Kelly. It was written by Daniel Gonzalez, Michael Squires, Josh Susong and Nicole Carroll.