Moai
Moai are monolithic stone statues on Easter Island. The more than 600 known Moais are distributed around the entire island. Most of the moai were carved out of the rock at Rano Raraku, where nearly 400 more moai remain in various stages of completion. The quarry there seems to have been abandoned abruptly, with half-carved statues left in the rock. Practically all of the completed moai were subsequently toppled by native islanders in the period after construction ceased. Although usually identified as "heads", many of the moai have shoulders, arms, and torsos, which have become buried over the years. The meaning of the moai is still unclear, and many theories surround these statues.
The most common theory is that the statues were carved by the Polynesian inhabitants of the islands 500 or more years ago. They are thought to have been representations of deceased ancestors (as grave markers), or perhaps important living personages, as well as family status symbols. They must have been extremely expensive to craft; not only would the actual carving of each statue require years of effort, but they would then have to be hauled across the island to their final locations. It is not known exactly how the moai were moved, but the process almost certainly required wooden sledges and/or rollers.