In 1692, Edmund Halley, not yet of comet fame, argued that inside the earth nested a series of spherical shells, like Russian dolls, each with their own atmosphere, magnetic poles and rate of rotation.

The belief has survived to the present day, the Hollow Earth Society now claims 400 members in more than 30 countries. Yet stories that Adolf Hitler and some of his followers escaped to hollow lands within the Earth after World War II (via an entrance in Antarctica) have been branded nonsense.