WATCH: See inside a smuggling tunnel under the U.S.-Mexico border

Inside a U.S.-Mexico cross-border drug tunnel Footage shows the path of a smuggling tunnel stretching across the U.S.-Mexico border discovered during a drug investigation.

U.S. law enforcement officials have discovered a smuggling tunnel that stretches from Tijuana, Mexico, to San Diego, California.

In the video above, the passage, located some 18 metres underground, has reinforced walls, a rail and ventilation system, and electricity.

U.S. authorities said they found the 530-metre path during a federal drug investigation, which led to charges against six people.

Watch the video at the top of this article.