SAN DIEGO (AP) — A nearly half-mile-long tunnel leading from Mexico to San Diego was discovered and more than a ton of cocaine and seven tons of marijuana was seized, the US attorney’s office said Wednesday. Six people were arrested. The tunnel extends 300 yards from a house in Tijuana, Mexico, to the border and then 500 yards on the U.S. side to a fenced lot in a San Diego industrial area. The tunnel was equipped with a rail system, ventilation, lights and a large elevator, officials said. The exit on the US side is about 3 feet wide and was covered by a trash bin. The six people arrested in San Diego on Friday were charged with crimes involving drugs and construction of the tunnel. The discovery demonstrates the enduring appeal of tunnels to smugglers, despite the significant time and money required to build one. Dozens of tunnels have been found along the US-Mexico border in recent years, some equipped with hydraulic lifts and electric rail cars.