At Lukeville, Arizona and Sonoyta, Sonora, the Organ Pipe Cactus National Monument meets the bio-reserve in Mexico known as the Gran Desierto de Altar, a vast and beautiful but harsh natural area covering much of the northwestern corner of the Sonora state.

Mexican Route 2 traversing the park along the northern edge is mostly an untraveled road.

As the road nears its western end, signs boast in English that the area is a "hassle-free zone," meaning vehicles from the U.S. and Canada can enter northern Sonora without having a vehicle permit: a public relations move meant to draw tourists.

Three hours north of Lukeville lies the vast complex of the Central Arizona Detention Center run by the private company, Corrections Corporation of America (CCA) in Florence, Arizona.

CCA, in coordination with the Department of Homeland Security, has detained thousands of Mexican migrants in this facility over the last decade.

If Mexican Route 2 is a "hassle-free" zone, then the road through Florence is anything but.