The Smoky God
Willis George Emerson
 For two years Jansen lived with the inhabitants of an underground network of colonies who, Emerson writes, were 12 feet tall and whose world was lit by a "smoky" central sun. Their capital city was said to be the original Garden of Eden. Later works by other authors, such as Agartha - Secrets of the Subterranean Cities, have identified the civilization Jansen encountered with Agartha (a mythical subterranean city), although Emerson did not use the name.