"Ahu" are stone platforms on which many moai sit. There are 313 known ahu and 125 of these carry moai. The biggest, Ahu Tongariki is 220 m (720 ft), and had the most (15) and tallest moai.
This is technology that will not go away. And to risk it moving into the hands of a terrorist group like al Qaeda or to other focused enemies of the United States, would have tragic consequences.