"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.
It was at Bell Labs that I first made direct contact with real semiconductor experts and thus began to fully understand what amazing materials they were and what they could do.