Puna Pau is one of Rapa Nui's many volcanos and was the main quarry for the pukao, the red circular stone that represented the headdress on top of the moai statues. The red volcanic rock, called scoria, is very soft and hence the carving is relatively easy. Due to its high iron contents and size a pukao can easily  influence the compass reading.

 

Puna Pau is located just northeast of Hanga Roa and from the top you have a nice view over Rapa Nui's only village.

 

Pukaos seem to have been a relatively recent addition to the moais since only 10% of the giants owned one.

Being circular, it is assumed the pukaos were simple rolled to their final destination and there put on top of the host moai.

 

Several finished pukaos still lay around waiting for transport. That probably will not happen soon.