U.S. authorities said Wednesday that they discovered the longest smuggling tunnel ever found along the southwest border. The tunnel stretches from Tijuana, Mexico, near the Otay Mesa Port of Entry to the San Diego area, covering 4,309 feet (1,313 meters). The second-largest tunnel was 2,966 feet (904 meters) and was discovered in 2014.
According to the U.S. Customs and Border Protection, the tunnel has an extensive rail/cart system, forced air ventilation, high voltage electrical cables and panels, an elevator at the tunnel entrance, and a complex drainage system.
The tunnel is about 5.5 feet (1.68 meters) tall, and 2 feet (0.61 meters) wide and is about 70 feet (21..3 meters) below the surface.
Authorities said several hundred sandbags were blocking a suspected former exit of the tunnel in the Otay Mesa warehouse district with the U.S.
The tunnel runs under several warehouses in the Otay Mesa area.
Authorities believe the tunnel exited in San Diego at one time, based on its trajectory.