San Luis Río Colorado, Mexico

Border tunnel: U.S. authorities have discovered an unfinished and unusually sophisticated smuggling tunnel running from Mexico to the U.S. underneath the border wall. The 1,300-foot reinforced tunnel starts in a neighborhood in San Luis Río Colorado and runs to San Luis, Ariz., where it stops short just before the surface. Measuring 3 feet wide by 4 feet high, the tunnel has a railway, ventilation, water lines, and electric lights. Angel Ortiz, an agent with Homeland Security Investigations, said its builders must have been highly skilled, because the sand in the area is very loose and most tunnels “end up caving.” The tunnel was found when agents noticed a sinkhole opening up near the border wall.