Drug cartels are digging tunnels into the U.S. to transport massive amounts of marijuana and other narcotics from the border onto American soil. The Feds have managed to shut down many of these tunnels and capture a key cartel manager, but this is just the beginning:

The land east of Otay Mesa, around the agricultural towns of Calexico and Mexicali, is a terrible place to build a sophisticated drug tunnel. The soil is unstable, and the All-American Canal, an eighty-mile-long aqueduct that surrounds Calexico, presents a formidable obstacle. Still, the cartels have found a way.

In October 2008, Mexican authorities, responding to reports of a cave-in and flooding near the canal, discovered a tunnel unlike anything they’d ever seen. Only ten inches wide, it was essentially a pipe. The Mexican cops traced it back to a house about 600 feet from the border, where they found a tractor-like vehicle with a long barrel on its side—a horizontal directional drill, or HDD. Used by oil, gas, and utility industries to quickly bore conduit holes over significant depths and distances, this drill was believed to belong to the AFO. It was the cartel’s first known attempt to use cutting-edge industrial equipment to build—in the most literal sense of the word—a drug pipeline.