This examination of three separate killings along the USA-Mexico border shines a spotlight on the violence there and why Donald Trump wants to build a wall.

An immigration officer must protect the U.S. border in Los Angeles from those trying to pursue the American Dream, as those around him try to break the rules by fraud, blackmail, and work-site enforcement. Immigrants from around the world enter Los Angeles every day, with hopeful visions of a better life, but little notion of what that life may cost. Their desperate scenarios test the humanity of immigration enforcement officers. In Crossing Over,...

"This ABC News program studies the connections between 9/11, the American economy, and the workforce of undocumented labor on which that economy increasingly depends. Interviews with Arizona border patrol agents evoke their frustrations and reveal the perils faced by many Mexicans who attempt desperate wilderness crossings. Contrasts between President Bush's proposed guest worker program and the Department of Homeland Security's efforts to crack down...