"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.
The novel succeeds on terms exclusive to literature. A good film succeeds on terms exclusive to the cinema. That's why so many bad novels can become good movies, like 'Jaws' or 'The Godfather.'