Clearly creations of a pre-dynastic advanced technology culture, the Colossi were originally 2 single pieces of quartzite quarried from a source some 400 miles or 650 kilometers from their present location; the quarry being near Cairo.
They are seated on bases that each weigh some 300 plus tons. How were they transported; who made them and when? Just another example of monumental engineering creations that academics can not explain.