"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.
A couple of times a day I sit quietly and visualize my body fighting the aids virus. It's the same as me sitting and seeing myself hit the perfect serve. I did that often when I was an athlete.