The Tecate, CA, border crossing, just east of the San Diego-Tijuana crossing, in March 2005  This older topographic map does not show the many warehouses on the USA side and the Maquiladoras on the Mexican side -- often with high fences and razor wire.  Parts are collected on the USA side before being moved to assembly factories on the Mexico side and assembled items are also collected in the USA warehouses before shipped to market.. The USA border here consists of two "walls:" 1) a steel-plate wall, which was constructed from steel plates used in the first Gulf War in the deserts of Kuwait and Iraq. By erecting them horizontally, people can more easily climb these walls than if these corrugated walls had been placed vertically! 2) a wire-fence  with several large openings from vehicles to drive through. Neither walls have razor wire on top of them, as the adjacent factories and housing projects do on the Mexican side. Is the USA government really trying to keep illegal immigrants out? Border patrols are scattered on top of the higher elevations along the border looking with their binoculars for illegals. Along parts of the border, roller-brushes are pulled behind vehicles on dirt roads so as to reveal footprints by illegals.
Click on a picture to see a larger view.