As editor of Amazing Stories and Fate, Ray Palmer was the first major commercial exploiter of flying saucers. He promoted some exotic UFO theories, notably that saucers were based inside a hollow Earth.

Mary Evans Picture Library

In the early 19th century an American eccentric, John Cleves Symmes (1779-1829), sought funding for an expedition to enter the Earth through one of two 4,000-mile wide polar holes. Inside the Earth, he was convinced, a benevolent advanced civilization existed.

Though an object of derision to most people, some took him seriously, and the idea of a hollow Earth was championed in a number of books throughout the rest of the century and right into the next.

Today, hollow-earthers believe flying saucers zip in and out of the polar holes. The people inside are descendants of Atlantis and its Pacific equivalent, Lemuria.

There is even a strong Nazi wing of the movement. According to Canadian neo-Nazi Ernst Zundel, the principal advocate of this theory, Hitler and his elite troops escaped with their saucer technology into the hole at the South Pole.

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