What a terrible shame that the beauty of this historic site was defaced because of the usual war monger mentality. It seems pretty obvious to me, looking at all these megalithic structures and sculptures, that at the time, these people knew how to "industrialize" many forms of corrosive acids, and manipulate the liquids behavior to eat away at the stone. Essentially making tools like chisels and picks obsolete. It would also explain the lack of tool marks at all these locations. We are simply underestimating our ancestors ingenuity.