There really isn't any conspiracy theory so outlandish that people won't believe it. I give you Tartaria and the global mud flood as an amusing and harmless alternative to the anti-vax nonsense killing people as I type: Inside the ‘Tartarian Empire,’ the QAnon of Architecture [bloomberg.com]
For proof you naysayers need look no further than the fish symbol which evokes the thought of tartar sauce.
Extant architectural remnants include the double arch M, ubiquitous in it's majesty and mega magisteria.
Flat-Earth, Ancient Aliens, Microchips in the Vaccine, 9/11, "The Deep State" (tho depending on your actual definition...), QAnon, the list is myriad & strange, as are the proponents...