Hollow Earth


The Hollow Earth is a historical concept proposing that the planet Earth is entirely hollow or contains a substantial interior space. Notably suggested by Edmond Halley in the late 17th century, the notion was tentatively disproven by Pierre Bouguer in 1740, and definitely by Charles Hutton (1778).
It was still occasionally defended in the early-to-mid 19th century, notably by John Cleves Symmes Jr. and Jeremiah N. Reynolds, but by this time was part of popular pseudoscience and no longer a scientifically viable hypothesis.
The concept of a hollow Earth still recurs in folklore and as the premise for subterranean fiction, and a subgenre of adventure fiction (Journey to the Center of the Earth, At the Earth’s Core).