It's Not A Mirage | Arizona Highways
On the way to the desert oasis of Quitobaquito Springs, Puerto Blanco Drive parallels the border with Mexico for about 13 miles through Organ Pipe Cactus National Monument. West of Lukeville and the Mexican town of Sonoyta, the border fence, designed as a pedestrian barrier, undulates up a hillside studded with saguaros before ending abruptly. The high mesh fence of oxidized steel then gives way to a low rail-and-post barricade intended to prevent vehicles from crossing into the United States while allowing wildlife to pass through.
Source: arizonahighways.com