The United States-Mexico Border is 3,183 km long, running overland for 1,117 km and along rivers for 2,066 km (see Figure 1). Geographically, the border area is a desert plain broken by a mountainous zone in the region of the two Californias. The border’s highest altitude is 1,200 meters above sea level, which is reached where the border passes by Dtiuglas, Arizona (U.S.A.) and Agua Prieta, Son...