http://www.skygaze.com/content/strange/HollowEarth.shtml
(excerpt)
W. C. Hefferlin wrote Amazing about his adventures in Rainbow City, an
abandoned extraterrestrial metropolis under the Antarctic ice. Though
its inhabitants were long gone, they had left their advanced technology
in place. Hefferlin's account of the space people's secrets failed to
impress those readers who knew something about science; they wrote to
jeer at the Rainbow City man's elementary errors, causing Hefferlin to
drop out of sight for a year. He reappeared under the sponsorship of
Borderland Sciences Research Associates, an occultoriented group
headquartered in Vista, California. In various BSRA publications
Hefferlin and his wife Gladys related that Rainbow City's inhabitants
were a race that had settled on Mars to escape the evil
Snake People. When the atmosphere of Mars became unbreathable, they
emigrated to earth and settled in seven great cities (Rainbow City being
the greatest of all) on the continent of Antarctica, then a tropical
paradise. Unfortunately, the Snake People found out where they were and
attacked, scattering the settlers all over the earth and, incidentally,
tipping the earth over on its axis, which is how Antarctica got to be
such a frigid place.
Rainbow City was revived in 1951, in Robert Ernst Dickhoff's
self-published Agharta: The Subterranean World, and again in 1960, in
Rainbow City and the Inner Earth People, by Michael Barton, writing as
Michael X. Barton also revived the Shaver mystery, reporting that
Venusians and Masters were allied in a struggle to wipe out the deros.
He further claimed to be receiving psychic communications from the
long-deceased Marshall Gardner, who enthusiastically endorsed Barton's
book.
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