The tallest building in the world for 4,000 years

This picture is almost unreal. If you click on it to view it enlarged you get a sense of how tall the tallest pyramid is.

Interestingly, the idea that the pyramids were built by slaves is being challenged. A nice article on the subject is here, from Harvard Magazine. Recent evidence for a paid skilled labor force includes tremendous quantities of unearthed cattle, sheep, and goat bones presumably used to feet the workers. Why would slaves have eaten so well? Ancient graffiti also includes scribblings like "Friends of Khufu" which most likely corresponds to a team of workers, not a pack of slaves.