Here's another picture--an elevated shot of the twin towns of Nogales, Arizona, USA and Nogales, Sonora, Mexico. It's very easy to see the location of the border. It is the fence along which the cars are parked--the tree in the bottom right overlaps the border, and the US immigration and customs building in the center of the picture is right up against the border (actually six inches inside the border at this point).
Enjoy
Dallen
<<Great Border Shot.jpg>>