http://www.wral.com/news/6473548/detail.html

SAN DIEGO -- A customs agent says a nearly half-mile long tunnel under the U.S.-Mexican border is "like being in a cavern or a cave."

Officials said they found more than two tons of marijuana in the tunnel, which starts near Tijuana's airport and ends inside a warehouse in California.

Mexican officials found their end of the tunnel Tuesday. U.S. officials found the exit Wednesday.

It's about 5 feet wide and high enough for an adult to stand up. It has a cement floor and is lined with lights.

U.S. Immigration and Customs Enforcement officials said the 2,400-foot tunnel is longer than most of the 21 cross-border tunnels found since the Sept. 11, 2001, attacks.

A customs agency spokeswoman said the discovery prompted federal prosecutors to open a criminal investigation. Four tunnels have been found in the area this month.