built by people thousands of years ago using nothing but their ingenuity and their own strength?
They nearly certainly used large tools, and probably beasts of burden (or slaves). If they were clever enough to figure out astronomical alignments, they definitely would have been able to fashion scaffolding and levers.
They nearly certainly used large tools, and probably beasts of burden (or slaves). If they were clever enough to figure out astronomical alignments, they definitely would have been able to fashion scaffolding and levers.