European Subterranean Paradise

The idea that our planet consists of a hollow, or honeycombed, interior is not new. Some of the oldest cultures speak of civilizations inside of vast cavern-cities.. Inhabitants who are the remnants of antediluvian civilizations, which sought refuge in hollow caverns inside the earth. http://www.amazon.com/Robert-Sepehr/e/B00XTAB1YC/

Gods with Amnesia:
Subterranean Worlds of Inner Earth
https://www.createspace.com/6159364