Start with a Great Pyramid of Giza, or locally sourced substitute following the traditional recipe [1]: * 5.5 million tonnes of limestone * 8,000 tonnes of

Start with a Great Pyramid of Giza, or locally sourced substitute following the traditional recipe [1]: * 5.5 million tonnes of limestone * 8,000 tonnes of granite * 500,000 tonnes of mortar For a simple approximation, we ignore ingredients that are not limestone. mass of limestone in great pyramid of giza = 5.5 * 1e8 kg of limestone Volume of limestone in one great pyramid of giza, assuming medium-high density limestone at 2500 kg / m^3 [2] = 5.5 * 1e8 kg / (2500 kg / m^3) = 2.2 * 1e5 m^3 allegedly there are 4.168e+9 m^3 cubic metres per cubic mile. That gives about 19,000 great pyramids of giza per cubic mile. [1] https://en.wikipedia.org/wiki/Great_Pyramid_of_Giza#Materials https://en.wikipedia.org/wiki/Great_Pyramid_of_Giza#Material... [2] http://www.natural-stone.com/limestone.html http://www.natural-stone.com/limestone.html edit: when i try to estimate by geometry from the pyramid dimensions, instead of by density, i end up with about 2,000 great pyramids of giza, but that's without trying to understand what the volume of a pyramid actually is, because i am not clever enough to do that.