The moai are carved from a type of volcanic rock called tuff. Most are between 3 and 6 metres tall - about the height of two classrooms stacked on top of each other - but the tallest ever made is over 20 metres. They all have large heads, long ears and strong chins. Many are set on stone platforms called 'ahu' facing inland, watching over the villages they once protected.
Carving the moai was just the beginning. Moving them across the island, with no wheels and no horses, was an enormous challenge. Scientists think the Rapa Nui people used ropes and wood to 'walk' the statues in an upright rocking motion - tilting them side to side, just like you might rock a heavy wardrobe across a floor.
Easter Island belongs to Chile even though it is so far out in the Pacific. People fly there from the Chilean mainland - it is a five-hour flight. The Rapa Nui people who live there today speak their own language, which is related to languages spoken by Pacific Island communities thousands of kilometres away - showing that ancient Pacific people were brilliant navigators.
Some of the moai have red 'hats' called pukao, carved from red volcanic rock from a different part of the island. Archaeologists have found that many moai were originally painted with bright colours. Imagine seeing a whole hillside of painted giant stone faces - it must have been an extraordinary sight.