"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.
At some point, I would like to write a book and other things, but I work best when there is some sort of deadline in my own mind, but not when fifty people or fifty million people are breathing down the back of my neck.