Imperial Beach, San Diego Sector, California, 2010. Built in 2006 and 2007, 15 feet high, $4 million to $6 million per mile.
(image 1 of 8)Yacumba, San Diego Sector, California, 2008. Built in 2007, 18-foot-high metal structure, $6 million per mile.
(image 2 of 8)Otay Mountain, San Diego Sector, California, 2010. 18-foot-high metal structure, $16 million per mile, over 3.6 miles of a 3,500-foot mountain peak.
(image 3 of 8)Imperial Desert, San Diego Sector, California, 2010. Built in 2007, 15-foot-high metal structure, $10 million per mile.
(image 4 of 8)