Organ Pipe National Monument. Pima County AZ. Its southern boundary is the Mexico border. I t is hard to comprehend that a line on the map that wasn’t there before 1853 could make such a difference. the south Puerto Blanco Road runs right along the fence/traffic barrier. On the other side in Mexico Hwy 2 with roadside businesses and a steady stream of traffic. Many trucks. And a small convoy of Mexico Border Patrol. They have a different style from their U.S. counterparts. Very distinctly military with camo pickups with a machine gun mounted on the roof with a soldier standing at in the bed. The weather, the trees and cacti, the pronghorn and coyote, and nature itself do not recognize this boundary. The same for The People (Tohono O’odham0 who have lived here for generations. The Sea of Cortez and the souhern end of the Sonoran Desert is only 70 miles away