The Department of Homeland Security’s Port Isabel Detention Center near Brownsville, Texas, looks like a prison, surrounded by barbed wire and guards, and it smells like a hospital, sterilized by disinfectant. Inside the waiting room, there are signs posted in English and Spanish reminding visitors, “Do Not Leave Children Unattended.”

Under normal circumstances, these signs likely would have gone unnoticed. But at Port Isabel, where the government houses hundreds of immigrant parents who have been separated from their children, they were impossible to ignore.