There are those who believe that the great architectural marvels of the past were not designed in their time, but are the remnants of a lost civilization called the Tartarian Empire. This theory is akin to that of ancient aliens, since no one in, say, ancient Egypt was smart enough to build the pyramids (fact check: they were). All the great technology that popped up in different parts of the earth were influenced by this empire, which was somewhere in Central Asia. But it was destroyed by the powers that came after it, and erased from history so that others could take the credit. In some versions of the conspiracy theory, Marco Polo was in on the suppression of the knowledge of Tartaria, and in others, Napoleon and the Russian Tsar made sure that Tartaria never made it into our history books.
The secret of the fictional Tartarian Empire is that they had harnessed the production of unlimited free energy. How they did this is lost to civilization, or was a secret kept so well no other nation knew about it, like Wakanda. While the theory arose in Russia in the 1970s, those who believe point to the 1915 World's Fair in San Francisco as proof of the existence of Tartaria. Read about this really weird conspiracy theory at Messy Nessy Chic.
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