Good question Dr BTC man.

Often times I do wish people like Ben who post these topics would explain what is being hinted at instead of making it so vague. 

With the Tartaria story, it’s basically said that there was a high society of people (similar to Atlanteans) who lived up above China and Russia and whom ruled the world peacefully across the globe. 

It’s said that this tartarian society had advanced technology, building techniques, free energy, sound wave healing, etc. Then the parasites or ruling class bloodlines who control the world today killed them all around 1700s-1800s mostly through large scale weather modification programs (earthquake, fires, mud floods) and even Direct energy weapons. 

So to conclude your question, what people believe is that there were many more people on the earth than we were told before this time and most of them were the tartarian people, once wiped out the controlling class came in and inherited all the cities and property. San Francisco happens to be a major Tartarian talking point because of all the buildings which existed during the worlds fair but now vanished. 

If I missed anything, feel free to throw in more Tartarian lore - Nostr people.