“Successful tunnel-building requires engineering, planning, equipment, money, and a lot of hard labor. But the Nogales Tunnel Task Force has found that with enough incentive, people on the Mexican side of the border in Nogales continue to find better ways to dig sometimes complex tunnels under the border to smuggle drugs. Tunneling itself, in fact, is a subsidiary business to the drug-smuggling trade, requiring skilled labor.”
Source: Drug smuggling tunnels become longer, increasingly sophisticated – Havasu News: News
