One which suggests that what lies underneath may be more than can ever be imagined - a whole other world located inside our own.
An 'Out There' ('In There') Theory
Although many in the scientific community may call this alternative theory "bizarre" and "irrational", for centuries there have been some who believed that the Earth is, in fact, hollow and supports an "inner" world that may or may not be inhabited by extra-terrestrial beings, an advanced race of "super-beings" that travel to and from the surface in ships we would perceive to be UFO's.
The theory proposes that our Earth is actually a shell with 800 mile-wide walls, which opens and exits at the Arctic and Antarctic. The "holes" are 1400 miles in diameter and curve from the outside of the shell inwards, further proposing that you could, theoretically, travel over this smooth edge and not even know you have entered this inner realm. What's more, an inner star, very similar to the Sun our planet orbits around, gives warmth to the inhabitants of this inner world and is 600 miles in diameter. It is said to emit gas that escapes to the "outside" world and creates the Aurora Borealis.
Major cave systems make up this inner world with smaller openings thought to be in cave networks in North America.
Entering the Hollow Earth
The idea was first brought forth in mainstream scientific circles in the 1700's, when noted astronomer Edmond Halley (he computed the orbit of Halley's Comet) put forth, while trying to explain anomalous compass readings, that the Earth consisted of 3 different sized spheres that surrounded an inner core. All these shells were separated by atmospheres and rotated at different speeds.
The scientific community dismissed these ideas and has continued to, although over the decades many scholars, spiritualists and authors have written about the concept, whether in fictional adventures, such as A Journey to the Centre of the Earth by Jules Verne, or books supporting the notion.
Many proponents of the Hollow Earth Theory, and some conspiracy theorists, believe that in February 1947 (the same year UFOlogy took off due to sightings made by Kenneth Arnold, and a possible crash of a flying saucer in New Mexico), a noted aviator and navigator by the name of Richard E. Byrd entered the Inner Earth via the North Pole, and wrote about his experience in notebooks afterwards. He is said to have seen a woolly mammoth there, a huge "shimmering"city made of crystals, and was warned by an inhabitant there about the use of atomic weaponry on the surface. He was also told that attempts had been made by their race to warn Humanity of the path we were taking, and the futility of War.
Sceptics have argued that if notebooks were written by Byrd himself, they have been taken out of context, misinterpreted and blown up into a "fantastical tale of delusion."
Many also believe Adolf Hitler was a proponent of the theory, and tried to find the entrances to make contact with the inhabitants of Inner Earth. It is believed he and other Nazis really disappeared into caves at the Arctic after WWII ended, in pursuit of the inner world.
Many cryptozoologists believe creatures such as Bigfoot and the Yeti are inhabitants from the Inner Earth, and some believe that creatures that may reside in major caves inside the Earth may be what we have named Goblins, Trolls, Gnomes etc.
Does it Exist?
Science has only reached a certain number of miles below the surface, the deepest hole drilled to date is the Z-44 Chayvo oil well which is 12,376 m (40,604 ft) deep, part of the Exxon Neftegas Sakhalin-I project; thus, visual knowledge of the Earth's structure extends that far.
What do you think, are we being told the truth in school?
Is our planet really hollow, not solid like we are taught?
Are there beings, human or not, dwelling in caves extending deeper into the Earth?
Or is this just more interesting fiction?
Put together by Ashley Hall 2014