The dim tunnel passage hugs narrow, winding concrete steps that lead 55 feet down, with a ceiling no higher than 4 1/2 feet, making it a claustrophobe’s nightmare. The underground passage stretching from Tijuana, Mexico, to a warehouse in California near the Otay Mesa Port of Entry known as “Buy 4 Less” is about 2,000 feet long and features reinforced walls, rail, ventilation, and electrical systems. The U.S. Attorney’s Office for the Southern District of California said on June 1 that the tunnel had been discovered during a Homeland Security investigation involving a suspected drug smuggling operation. Four people were charged with conspiring to distribute more than a ton of cocaine worth $45 million. Authorities said the discovery dealt a blow to the Jalisco New Generation cartel....