A U.S. Coast Guard cutter off Costa Rica saw a strange disturbance just below the ocean surface in 2006: three snorkels poking out of the water, and no diver's flag.
As they got closer, the disturbance was revealed to be a homemade submarine, made in the jungles of Colombia. It was carrying three tons of cocaine to the United States.
These homemade submarines have been dubbed "semi-subs," and they've become more than just a nuisance in the international drug trade.
Host Scott Simon speaks with David Kushner, who wrote an article about the semi-subs appearing in the Sunday's New York Times Magazine.