Most of the border between the United States and Mexico is marked by the Rio Grande, a river crossed by 28 bridges. Every day, 250,000 people, 12,000 trucks and 5,000 railcars cross them, illegally or otherwise. For the first time, cameras were allowed on these bridges to film the way border patrols work. Thanks to a rigorous approach and technological tools, American agents manage to keep the cou
