Perhaps the most intriguing photo purporting to show the North Polar opening into the “Hollow Earth”, taken by the American space station Skylab in 1974.

There are a myriad of conspiracies concerning “Hollow Earth”. Some people contend that the earth is really hollow inside and that there are 1400 mile diameter entrances at the north and south poles. Both of these entrances are said to be usually covered in clouds and the airspace is restricted by law. The earth’s crust is supposedly 800 or so miles thick and then after that you reach inner Earth.

In mythology the name given to this inner Earth is Agartha. There is said to be a sun in the center and there are vast civilizations with great technology and natural resources. There are also said to be many extinct animals such as dinosaurs and mammoths that exist there.

Scientist-astronaut Owen K. Garriott, Skylab 3 science pilot, is seen performing an extravehicular activity at the Apollo Telescope Mount (ATM) of the Skylab space station cluster in Earth orbit, photographed with a hand- held 70mm Hasselblad camera.  Garriott had just deployed the Skylab Particle Collection S149 Experiment.  The experiment is mounted on one of the ATM solar panels. The purpose of the S149 experiment was to collect material from interplanetary dust particles on prepared surfaces suitable for studying their impact phenomena.  Earlier during the EVA Garriott assisted astronaut Jack R. Lousma, Skylab 3 pilot, in deploying the twin pole solar shield.