A recently discovered deep sea snail, the scaly-food gastropod, has a shell that is impressively developed. So much so, that the u.s. Military is trying to use its design to inspire defensive layers in military armor.
"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.