Moai are statues carved from compressed volcanic ash on Rapa Nui (Easter Island). The statues are all monolithic, that is, carved in one piece. They may weigh more than 20 tons and be over 20 feet tall. The largest moai erected was almost 10 metres high and weighed 75 tonnes.

Less than one-fifth of the statues once had red stone cylinders (pukau) placed on their heads. These "topknots" were carved in a single quarry known as Puna Pau.

About 95% of the 887 moai known to date were carved out of compressed volcanic ash at Rano Raraku, where 394 moai still remain visible today. The quarries in Rano Raraku appear to have been abandoned abruptly, with many incomplete statues still in situ. Practically all of the completed moai that were erected upright on ceremonial platforms were subsequently toppled by native islanders in the period after construction ceased.