"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.
In 1975, the Banqiao Dam in China was among many dams that were destroyed after the extreme rains of Typhoon Nina. It is estimated that between 90000 and 230000 lives were lost as a result of the Banqiao Dam breaking.