The picture with the tree at the top of the wall:.. Has anybody ever dug into the ground behind the wall to see how many vertical layers are entertwined with the face of the wall. Is it backfilled with nicely cut stones or just filled with rubble?

https://www.youtube.com/watch?v=gcdToc0ibbQ&t=269s

This morning I watched this video and it is very informative about these types of megalithic sites. It starts at Easter Island and works around the globe to Indonesia. If you got a couple of hours it would be well worth the time.