Some of its adherents claim it was all covered up by the "great mud flood", while others claim that many current buildings, such as medieval cathedrals or even later buildings, are evidence of its truth as they could not have built with the technology available at the time. Buildings with demi-basement windows are also "evidence" of the mud flood as those demi-basements were "obviously' fully above ground at the time that they were built.
I find the mud flood fantasy particularly amusing as I work in a UNESCO World Heritage Site and Grade 1 listed building, which has demi-basements; the original plans and architect's models still exist and show the demi-basements.
They also believe that the Tartarians had free energy, which they drew from the "aether", which is why many old buildings have spires or other pointy bits on the top.