"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.
Male dogs will raise their legs while urinating to aim higher on a tree or lamppost because they want to leave a message that they are tall and intimidating. Some wild dogs in Africa try to run up tree trunks while they are urinating to appear to be very large.