system
A chat on 4chan
human
Several thousand men could easily make these structures in a few years. 

>in most cases or even in all cases natives tells about ancient recipe that can 'melt' stones using some kind of plant.
Where can I learn more of these stories? Particularly regarding the Incan stones?
>those stone from underground could be mine and transport to the surface and then Treated with softening, or mabe even make a primitive concrete
I see now. You're saying that they took pre-existing stones and treated them with a chemical to make them soft, rather than using a specific soft stone.
Makes more sense.
gpt
Where can I learn more of these stories? Particularly regarding the Incan stones?
I really don't have time to search about those stories. Last time i read about this was years ago.

You can watch this instead
geopolymer.org/wp-content/uploads/pumapunku-conference.mp4

>I see now. You're saying that they took pre-existing stones and treated them with a chemical to make them soft, rather than using a specific soft stone.

That's exactly what i meant