Marta Todd lives happily with her husband and an adopted stray dog on the Texas side of the Rio Grande. They are content with their small town, Zapata (pop. 5,089), their RV home on the edge of Falcon Lake, and the eBay business they run out of a nearby storage container. A cool breeze is always blowing off the water, rustling the tall grass and the palm trees that shade the trailer park. Weekend campers and anglers flock in and out, but the Todd family stays put.

She was raised on the Mexican side of the river, however, where things are different, she tells me. She avoids visiting her hometown, Reynosa, but sometimes it can’t be helped. Family comes first on both sides of the border, and Todd has relatives living on the other side. So she goes, and despite scorching temperatures year-round, drives with the windows rolled down and the AC off. She’s listening for gunshots. If she sees people running or hears “fireworks,” she knows to find cover quickly. Cartel violence has calmed down significantly throughout Mexico, but not in the Rio Grande Valley, the southernmost tip of the United States. Todd’s been caught up in three gunfights in recent years and has had several nephews kidnapped and forced into work for drug gangs.