I’ve heard that as a society we don’t fully understand how the Egyptian Pyramids were built and that even with our modern construction equipment it would be a herculean task. I don’t know how true that is, but Wallace T. Wallington (odd name now that I write it) claims that using the methods he has formed during his 35-years as a carpenter, he could build the Great Pyramid of Giza in 25 years with the help of 640 people.
He’s already built a replica of Stonehenge without the use of any hoisting equipment, and he’s working on even larger projects to provide evidence to support his claims.
I should have paid more attention in physics.