"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.
No experience is a cause of success or failure. We do not suffer from the shock of our experiences, so-called trauma - but we make out of them just what suits our purposes.