"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.
At one of the annual conventions of the American Society for Aesthetics much confusion arose when the Society for Anesthetics met at the same time in the same hotel.