"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.
You know, I do music. If you look under the hood of the industry I'm in, it's all based on technology. From radio to phonographs to CDs, it's all technology. Microphones, reel-to-reels, cameras, editing, chips, it's all technology.