U.S. authorities found twenty tons of pot inside a warehouse in Otay Mesa, near San Diego.
Just across the border, Mexican troops raided another warehouse, with four more tons of pot inside.
They also discovered the entrance to a sophisticated tunnel, used to transport the drugs across the border from one warehouse to the other.
The underground cavern stretched about six hundred yards and was outfitted with lighting, ventilation, and even a rail system.
U.S authorities arrested two people believed to be transporting the drugs. But it's unknown at this time which cartel may have built the tunnel.