"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.
There is the glamour side of it, which allows you to meet great variety of people with whom you simply can have a good time, but there's also the sad side of it that drags you into a superficial and artificial world.