WATCH: rise of the super drug tunnels: California's losing fight against smugglers
Joe Garcia is a deputy special agent with the Department of Homeland Security and head of the San Diego Tunnel Task Force. His task force has found over 200 tunnels under the California-Mexico border since 1990. But every time they close a tunnel, smugglers build a new, better tunnel. "You can't fight markets," says David Shirk, associate professor of international relations and director of the Justice in Mexico project at the University of San Diego.