The notion was proposed by Athanasius Kircher's non-fiction Mundus Subterraneus (1665), which speculated that there is an "intricate system of cavities and a channel of water connecting the poles". [20] :137

World War II [ edit ] Letter from RADM Richard E. Byrd to Captain Irving R. Chambers, Commanding Officer, USS Concord, commemorating the loss of 24 men during Byrd's special mission to reconnoiter South Sea islands during September–December 1943.

In Legendary's series of Godzilla films, the hollow earth is the origin point of the titans, the monsters which are the focus of the films. In Godzilla vs. Kong (2021) the hollow Earth was a major location, with a large portion of the story being set in it.

It is often claimed that mathematician Leonhard Euler proposed a single-shell hollow Earth with a small sun (1,000 kilometres across) at the center, providing light and warmth for an inner-Earth civilization, but that is not true. Instead, he did a thought experiment of an object dropped into a hole drilled through the center, unrelated to a hollow Earth. [25] 19th century [ edit ] Byrd was one of only four American military officers in history entitled to wear a medal with his own image on it. The others were Admiral George Dewey, General John J. Pershing, and Admiral William T. Sampson. As Byrd's image is on both the first and second Byrd Antarctic Expedition Medals, he was the only American entitled to wear two medals with his own image on them. Even as unbelievable as the beliefs of Symmes and Teed were, as the Hollow Earth theory grew into the 20th century, it began to take on an even more supernatural air.After destroying Mechagodzilla and resolving his now ending rivalry with Godzilla, Kong decides to return to the Hollow Earth, making it his new home. There’s also a race of Giants—presumably from a much bigger genetic experiment, maybe something involving beanstalks—and Germans. Richard E. Byrd Elementary School, a Department of Defense school located in Negishi (Yokohama, Japan) opened on September 20, 1948. The name was changed to R.E. Byrd Elementary School on April 5, 1960. Many Hollow Earthers believe in “concave” Hollow Earths, otherwise known as skycentrism. The hypothesis says that we’re inside a hollow world, and it stands to reason that there are additional hollow worlds within our own. By using specialized equipment, they believe that they can prove this idea by studying coastlines around the world. The Hollow Earth is believed to be the natural habitat and evolutionary place of origin of all Titans. In ancient times, Kong's species warred against Godzilla's species for dominance within the Hollow Earth. Iwi legends suggest that the war ended in a Titanus Gojira victory and with the Kongs, and the Iwi who'd originally lived alongside them in the Hollow Earth, fleeing to Skull Island on the surface world [1].

It's heavily implied that the Hollow Earth is the source of global myths and legends about people emerging from the earth, due to Titans and the Iwi having lived there at one time before coming to the surface world. Ellen Russell Emerson, Indian Myths, 1965 "It is to the Cubans we are indebted for the following version of man's origin: It was from the depths of a deep cavern in the earth that mankind issued." William Fairfield Warren, in his book Paradise Found–The Cradle of the Human Race at the North Pole, (1885) presented his belief that humanity originated on a continent in the Arctic called Hyperborea. This influenced some early Hollow Earth proponents. According to Marshall Gardner, both the Eskimo and Mongolian peoples had come from the interior of the Earth through an entrance at the North Pole. [29] 20th century [ edit ] The Germans did make it to Hollow Earth, one theorist writes.“They made a deal with the people in the Hollow Earth.” A CBS radio station, KFZ, was set up on the base camp ship, the Bear of Oakland and The Adventures of Admiral Byrd program was short-waved to Buenos Aires, then relayed to New York. [41]Yenne, William (2003). "Adolf Hitler and the Concave Earth Cult". Secret Weapons of World War II: The Techno-Military Breakthroughs That Changed History. New York: Berkley Books. pp.271–272. ISBN 978-0-425-18992-4. The inner part of the planet also has many other humanoid creatures, some of whom aren’t aware of the outer Earth, and some of those creatures live to the age of 1,700. Why? Well, there aren’t any dangerous toxins in the Inner Earth. Duh. Rank and organization: Commander, United States Navy. Born: October 25, 1888, Winchester, Va. Appointed from: Virginia. The Egyptian mathematician Mostafa Abdelkader wrote several scholarly papers working out a detailed mapping of the Concave Earth model. [47] [48] In his book On the Wild Side (1992), Martin Gardner discusses the Hollow Earth model articulated by Abdelkader. According to Gardner, this hypothesis posits that light rays travel in circular paths, and slow as they approach the center of the spherical star-filled cavern. No energy can reach the center of the cavern. A drill, Gardner says, would lengthen as it traveled away from the cavern and eventually pass through the "point at infinity" corresponding to the center of the Earth. Gardner notes that "most mathematicians believe that an inside-out universe, with properly adjusted physical laws, is empirically irrefutable". Gardner rejects the concave Hollow Earth hypothesis on the basis of Occam's razor. [49] Portney, Joseph (2000). "The Polar Flap: Byrd's Flight Confirmed". Litton Systems, Inc. Archived from the original on September 16, 2009 . Retrieved July 11, 2007. See also Portney, Joseph (1973). "The Polar Flap: Byrd's Flight Confirmed". J. Inst. Nav. 20 (3): 208–18. doi: 10.1002/j.2161-4296.1973.tb01173.x.

Standish, David. Hollow Earth: The Long and Curious History of Imagining Strange Lands, Fantastical Creatures, Advanced Civilizations, and Marvelous Machines Below the Earth's Surface. Da Capo Press, 2006.The idea of a hollow Earth is a common element of fiction, appearing as early as Ludvig Holberg's 1741 novel Nicolai Klimii iter subterraneum ( Niels Klim's Underground Travels), in which Nicolai Klim falls through a cave while spelunking and spends several years living on a smaller globe both within and the inside of the outer shell. Richard E. Byrd Middle School in Sun Valley, California, is named after Admiral Byrd. The school opened in its present location in 2008 after its original location was converted to Sun Valley High School. There, he was ostensibly confronted by a member of an alien civilization. “We have let you enter here because you are of noble character and well-known on the Surface World, Admiral,” the alien said.