The large stone statues, or moai, were carved during a relatively short and intense burst of creative and productive megalithic activity. Although often identified as "Easter Island Heads", the statues actually are heads and complete torsos.
Almost all moais were carved out of distinctive, compressed, easily worked volcanic ash or tuff found at a single site called Rano Raraku. The Rapanui who carved them had no metal or powered machinery, only stone hand tools - mainly basalt toki.
Long sloping noses, strong brows, deeply inset eyes, and prominent chins characterize Moai. Some examples also wear a hat like cylinder made of red stone on their heads, which may represent a headdress or elaborate hairstyle. In their eye sockets, white coral with black obsidian pupils were placed. Their average height is roughly 13 feet, but they range anywhere from 8 feet to an unfinished example over 70 feet high.
Only a quarter of the statues were installed on the coastal ahu platforms.
Ahus are stone platforms that some of the Moai were erected on they have a retaining rear wall several feet high, usually facing the sea, with a platform behind the wall. A sloping ramp covered with evenly sized wave rounded boulders on the inland side of the platform rising most but not all the way up the side of the platform. Inside the Ahu was a fill of rubble.