U.S. and Mexican authorities are investigating what they call a a major cross-border drug tunnel.
Pictures released Wednesday show an underground passageway equipped with lighting, ventilation and an elevator system.
The unfinished tunnel originates in Tijuana and extends more than 860 feet into the United States. Officials from the U.S. Drug Enforcement Agency said it is investigating exactly where that is. Overall, the tunnel is just short of 1,000 feet in length, plunging at one point 90-100 feet below the surface.
More than a dozen individuals -- all of whom are believed to be Mexican citizens -- were found and arrested in the tunnel.
Investigators believe the tunnel was under construction for about two years.