Journalists climb into a cross border tunnel located underneath a water purifying plant in Tecate December 6, 2012. The tunnel, which is still under construction, was found due to an anonymous tip. It has no exit to the U.S. but a ventilation system, electricity and a water pump. Seven people who were found working on the tunnel when it was discovered have been arrested by the authorities, reported local media. REUTERS/Jorge Duenes (MEXICO - Tags: CRIME LAW)