"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.
Bjorn was a different breed, I threw my best material at him, but he would never smile, but that added to the charm when he played me and Mac. We were going nuts and losing our mind and he was sitting back like he was on a Sunday stroll.