Concerning Matters pertaining to the Geological construct of a Number of solid Concentrick Spheres which hitherto have been Bound within the Confines of the Earth, and the Entrances to such may be found amongst the Many caves and Caverns stretched across our Great Globe, as well as the Notion that the Poles (at this time it does not matter Which, and has even been Speckulated that there are, in fact, Four, that is, Twice the Number of the Two usually Perceived), and of the Societies, Creatures and Beings found within the Depths, which We shall see greatly varies in Terms of the overall Qualities and Character.
Timestamps:
introduction (0:00)
Ludvig Holberg - "Niels Klim's Journey Under the Ground" (1741) (16:36)
authorship disputed - "Symzonia: A Voyage of Discovery" (1820) (50:47)
Edward Bulwer-Lytton - "The Coming Race" (1871) (1:48:26)
Bibliography:
Standish, David. "Hollow Earth : the Long and Curious History of Imagining Strange Lands, Fantastical Creatures, Advanced Civilizations, and Marvelous Machines Below the Earth’s Surface". 2006