haxxiy on 23 August 2012
I think the important thing to keep in mind is that technology does not advance on a linear, inevitable march. Ancient cultures could have discovered stuff we only learned about a few decades ago but still don't know the wheel.
That being said, I'm certain the law of diminishing returns makes sure no 20th century technology is going to ever be found among ancient civilizations. You simply need too much research, too much money and momentum for some breakthroughs.
Unless, of course, there is some field of physics or biology that we somehow overlooked until now. Does those pyramids really harvest the energy of torsion fields? 
But that's very unlikely.
