While we see a lot of flat earth believers in our modern 21st century, which is mind-blowing

in itself, we tend to forget that that's not the only alternative model of the earth

to garner a share of believers throughout history.

Another popular one has been the hollow earth, in which the hollow interior is home to

an upside down alien society, living on that inverted surface.

Today we've got the surprising history of that idea, and that's coming up next UnSkeptoid.

Hey everyone, Brian here. A quick favor. We are conducting an audience survey.

We'd be really grateful if you could take just a few minutes and answer our survey.

This is the kind of thing that's sort of an engineering and marketing necessity to make the whole

free podcast ecosystem flourish. So please check it out. Also surveys are fun. You get to talk

about yourself. Please visit survey.prx.org slash Skeptoid to take the survey today. That's survey.prx.org

slash S-K-E-P-T-O-I-D. Thanks.

Today the prevailing hollow earth theory states that the earth is a hollow shell, with its inner

surface being much like the outer surface where we live. It has oceans, mountain ranges, and clouds,

and hovering at the very center of this hollow ball is a miniature sun that warms the inner

surface residents. Slightly offset from the North Pole and the South Pole are holes that allow

travel between the inner and outer worlds. The civilization that lives on the inner surface

is more advanced than ours, and they fly in and out through the polar openings in flying saucers,

which explains UFO sightings by the outer surface civilization. Only the government knows about

the polar openings and the inner civilization, and they suppress this information, ostensibly to

prevent other governments from finding out about it and claiming the territory.

To most of us, this sounds like a pretty far out concept. So many applications of various

...