In a desolate stretch of desert outside Yuma, Ariz., there's a spot where more than 350 migrants and children burrowed under the steel border fence a few weeks ago.
"This only goes down just about probably another foot, this steel," said Anthony Porvaznik, chief patrol agent for the Yuma sector of the Border Patrol. He says smugglers tried digging in more than a dozen different spots, looking for places where the ground was soft enough.
"This is very sandy," Porvaznik said. "It's like that all the way down, and so it was easy to dig."