SAN LUIS, Ariz. -- It's reminiscent of a mine shaft. Narrow hallways, low ceilings, and wood beams reinforcing the walls.
But this operation isn't moving earth, It's moving heroin and meth from Mexico to Arizona.
"The amount of money they poured into this one would lead me to believe someone is willing to invest a significant sum into trying to build some better tunnels to possibly get some harder drugs through in this area," said Doug Coleman, special agent in charge of the Drug Enforcement Agency in Arizona.
The DEA said what looked like a business struggling to open, was hiding an open pathway under the border, some 57 feet down and 755 feet across - the length of two and a half football fields.
It boasts ventilation and electricity, and the DEA believes those who built it had the help of engineers.
"It's a very complex job to construct a tunnel of this magnitude with this sophistication, with this length, because 750 feet is a long tunnel," remarked Coleman.
The DEA believes it took a year and a million dollars to complete the tunnel, and suspects that the sinaloa cartel foot the bill.
And while they may have found it early, the tunnel's design shows the drive to move drugs into Arizona is strong.
"What we find here in Arizona is just dug into the dirt or using the sewer system in Nogales or something along those lines so I can't think of one this sophisticated found in Arizona," added Coleman.