The underground world of Earth, studied, to put it mildly, not the best way.
For example, on old maps, there is a legendary underground city of Grustina. Even 300-500 years ago it belonged to Tartaria and connected the neighboring cities by underground passages. The city was under modern-day Tomsk, where even now underground passages and exits to the surface are known to many local residents.
It is interesting that the city is on many European maps, information about it can be found in the memoirs of merchants, monks, travelers, at different times have visited Russia. In Russian literature, however, mentions of such a miracle of architecture are destroyed, and remain only in Karamzin and Klyuchevsky.
Forbidden History
