A Mexican soldier flashes his torchlight inside a tunnel in Tijuana November 3, 2010. U.S. border police have found a sophisticated drug smugglers' tunnel the length of six football fields linking Southern California with Mexico and arrested two people, authorities said on Wednesday. Agents recovered more than 25 tonnes of marijuana in seizures related to the investigation in both California and Mexico and arrested a U.S. citizen and his Mexican wife. Picture taken November 3, 2010. REUTERS/Jorge Duenes (MEXICO - Tags: POLITICS CRIME LAW SOCIETY)
A look at various smuggling tunnels across the U.S.-Mexico border.