US officials say they have discovered the longest smuggling tunnel ever found on the border with Mexico.
Stretching for 4,309ft (1,313m), the tunnel had a lift, rail track, drainage and air ventilation systems, and high voltage electrical cables.
The passageway connected an industrial site in the Mexican city of Tijuana to the San Diego area in California.
There were no arrests made or drugs found. Authorities did not say who they suspected of being behind the tunnel.
But Mexico's Sinaloa cartel, described by the US government as one of the largest drug-trafficking organisations in the world, operates in the area. Its founder and long-time leader, Joaquin "El Chapo" Guzman, is serving life in prison in the US.
