The official narrative is that over 200 huge buildings were built for the Chicago Worlds Fair only to be torn down a few years later. Everyone believes that story, even though they wouldn't have been able to even complete the foundations of the buildings in time for the fair with 1893 machinery.
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Ancient Civilizations
The official story is that a large amount of those building materials were papier-mâché which could be mixed with the water available on-site.
My point was that theoretically the time it took to build the most-time consuming building is the time it would take to build all of them because you can build them all at the same time. The materials and logistics are another matter.