An incomplete tunnel found stretching from Mexico to Arizona appears to be "the most sophisticated tunnel in US history," authorities said. The tunnel intended for smuggling ran from a neighborhood in San Luis Río Colorado, Mexico, to San Luis, Arizona, where it stopped short of reaching the surface, the AP reports. It was built in an area that's not conducive to tunnels because of the terrain, and it had a ventilation system, water lines, electrical wiring, a rail system and extensive reinforcement, federal officials say. "What makes this one unique is that the terrain in Yuma is very hard ... the sand is very loose, and most of them end up caving," said Angel Ortiz, assistant special agent in charge for Homeland Security Investigations in Yuma.
"So the fact that the material was very well built and it had ventilation, it had water, it had a rail system with walls, roof, floor, electrical, makes this one a very unique type of tunnel," he added. Carl E. Landrum, acting chief patrol agent with the Border Patrol's Yuma Sector, said "this appears to be the most sophisticated tunnel in US history, and certainly the most sophisticated I've seen in my career." Homeland Security Investigations started excavating around the tunnel in late July after someone reported a sinkhole near the border wall. HSI already had reports of potential tunnel activity in that area, and the agency began drilling, Ortiz said. A camera was sent 25 feet underground, and the tunnel was discovered on Tuesday.
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