"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.
When the characters are really alive before their author, the latter does nothing but follow them in their action, in their words, in the situations which they suggest to him.