The 1.5-mile barrier along the U.S.-Mexico border was designed to keep cars from illegally crossing into the United States. There's just one problem: It was accidentally built on Mexican soil. Now embarrassed border officials say the mistake could cost the federal government more than $3 million to fix. The barrier was part of more than 15 miles of border fence built in 2000, stretching from the town of Columbus to an onion farm and cattle ranch. A U.S. Customs and Border Protection spokesman said the vertical metal tubes were sunk into the ground and filled with cement along what officials...