MEXICO. Sonora. Caborca. Sunday, May 9, 2021. “Prevention Through Deterrence” is a strategy introduced by the US Federal Government in the mid-1990s, which relies on the rugged terrain to impede the flow of people from the South. The strategy aimed to raise the risk of apprehension along traditional entry and smuggling routes by increasing the numbers of Border Patrol agents and the use of technology, thereby forcing illegal traffic over more challenging terrain. In the photo, an arrow is painted on a cactus at a crossing area near Altar, Sonora.