Mexican officials found a tunnel near the U.S.-Mexico border that they are describing as "very sophisticated."
Photographs of the tunnel show rails (similar to train tracks) on the ground, and walls and the ceiling covered with particle board. The tunnel was also wired for electricity, and in a photo released on Monday, one of the newer style compact fluorescent light bulbs is visible.
"An Energy Star qualified compact fluorescent light bulb (CFL) will save about $30 over its lifetime and pay for itself in about six months," according to energystar.gov. "It uses 75 percent less energy and lasts about 10 times longer than an incandescent bulb."
Investigators with Immigration and Customs Enforcement were with Mexican officials on Thursday when the tunnel was discovered near the Otay border cargo area. Authorities said the tunnel was located on the southern side of the border and that it did not cross the border.