How they did that? It seems they knew certain advance engineering methods we cannot even understand today! Q http://newsroom.ucla.edu/stories/easter-island-statues-revealed-234519 The famous heads of Easter Island's statues are actually heads with torsos that have become partially buried by erosion,... UQ Q https://en.wikipedia.org/wiki/Moai The production and transportation of the 887 statues[3] are considered remarkable creative and physical feats.[4] The tallest moai erected, called Paro, was almost 10 metres (33 ft) high and weighed 82 tons;[5] the heaviest erected was a shorter but squatter moai at Ahu Tongariki, weighing 86 tons; and one unfinished sculpture, if completed, would have been approximately 21 metres (69 ft) tall with a weight of about 270 tons. The islanders themselves tore down the standing moai after their civilization broke down. UQ https://badarchaeology.wordpress.com/tag/moai/
Thor Heyerdahl wrote a Book about it. Basically, you lever the object, put a tiny stone in the gap, and release the levers. Repeat 1000 times with slightly bigger stones and the head is upright. Amazing what people will do with time on their hands. The part of the book about their houses was the most interesting.