The Hollow Earth Theory is a theory just as erroneous as the Flat Earth Theory.  There are organizations that were made to promote these theories. As absurd as the earth being hollow sounds, let’s try to understand these theories and why people are so passionate about proving them to be true.  “My conception of the Hollow Earth, based on my research is that the shell of the Earth is about 800 miles thick, from the outside to the inner surface,’ says Rodney Cluff, author of World Top Secret: Our Earth IS Hollow.” according to Atlas Obscura.  

Supposedly the first person to scientifically speculate about a hollow earth was Edmund Halley.  Halley’s theory is that Earth is made up of layers of spherical shells spinning in different directions, encompassing hollow core.  

Again, according to Atlas Obscura.  “Proposed in 1692 as a way of explaining anomalous compass readings, Halley’s theory is that the planet is a series of nested, spherical shells, spinning in different directions, all surrounding a central core.”  In 1869, Cyrus Reed Teed declared the earth was hollow and that we all live in this sphere. The sun, all the stars and galaxies, and every planet inhabit the Earth’s interior. The Earth’s crust infinitely encases the universe.  “Motivated by his new cosmology, Teed published a book, started a new religion, amassed disciples, and founded a new town in Florida.” explains aeon online.