Tunnel Under The Rio Grande

Amazing, and interesting too! I wonder how digging that worked, because the point-to-point distance was likely substantial, and it should have taken a long time to accomplish (unless the city storm drainage system provided a short cut):

At approximately 1:30 a.m. CBP Border Patrol agents working near the Bridge of the Americas thwarted a narcotics smuggling attempt after becoming aware of suspicious activity in the city storm drain system. Upon closer investigation, agents discovered a juvenile suspect in possession of more than 200 pounds of marijuana.

...CBP Border Patrol and ICE agents working jointly initiated an in-depth investigation of the city storm drainage system and discovered an illicit man-made tunnel underneath the concrete lined Rio Grande River. Federal authorities from Mexico also responded to the scene and assisted with the identification of the exit point of the tunnel in Mexico.