The great Sonoran Desert stretches from deep in Mexico to the middle of Arizona, a dun landscape dotted with 20-foot-tall saguaro cacti and scraggly sagebrush. With its mind-blurring heat, this is not a place where you want to be left behind—but people are all the time. Ranchers, county sheriffs, and the government patrols that guard the United States–Mexico border find them with grim regularity, the bodies of illegal immigrants who slipped across the border but did not survive the journey on the other side. Remains not found for weeks or months may amount to a few decaying bones. Sometimes an animal drags the body off, or a person strips down under the onslaught of the heat, leaving behind nothing more than a pair of worn shoes and a faded shirt.
More than 200 bodies a year turn up in the Sonoran, a number that has increased over the past decade as immigrants avoid urban areas and attempt to reach the United States by more remote routes, often through Arizona. After crossing the border, they sometimes walk 70 miles or more to reach a safe point of entry, often traveling without water and in temperatures that can reach 110 degrees Fahrenheit.