Border Field Area, California

A zone along the US/Mexico Border between the Pacific Ocean and Interstate 5, with several remarkable land uses that combine to make one of the most unusual places in the country. Emerging from the Pacific Ocean, the border fence travels through bare, hilly terrain, north of which is a flat estuary. Illegal immigrants used to stream across the border in this region, which has recently been dramatically transformed by the Army and the Border Patrol to make surveillance and capture easier, as part of Operation Gatekeeper. The Tijuana River flows out of Mexico into this zone, and is so polluted that it has recently been contained in a pipe and is treated in a treatment plant like raw sewage before being discharged into the ocean. There is a major military helicopter training facility here, with helicopters flying low overhead on a nearly continuous basis. A park (Border Field State Park, located within the Tijuana River National Estuarine Research Reserve), is closed to vehicle traffic Monday-Friday, but is otherwise accessible to pedestrians, bicyclists, and equestrians, where one can put one's arm through a hole in the fence into Mexico, next to a strip of beach that was heavily strafed as a target site for WWII fighter pilots.