While walls, fences and virtual fences continue going up along the U.S.-Mexico border, frustrated smugglers have gone underground. But Nogales Border Patrol has its own countermeasure.

A 100-yard long, 12-foot deep “headwall” has been constructed of concrete and steel to keep would-be drug tunnels from penetrating beyond just a few feet from the international boundary line.

For this story and photos and more local news you can’t get anywhere else, see Friday’s edition of the Nogales International.

(Video courtesy of US Border Patrol)