"There are Imperial German maps that show the entire inner world of Agartha."
http://www.imperialgermans.com/hollowearth.html
"Agartha (sometimes Agartta, Agharti, Agarath,[1] Agarta or Agarttha) is a legendary kingdom that is said to be located in the Earth's core.[2] It is related to the belief in a hollow Earth and is a popular subject in esotericism.[3]"
https://en.wikipedia.org/wiki/Agartha
"A Map designed by cartographer Heinrich C. Berann is believed to show an entrance to the Inner Earth, the Kingdom of Agartha.
The Antarctic continent can be noted without its thick layer of ice in that map,.
But the most intriguing detail is the presence of underwater passages spanning across the whole continent and seem to converge at the exact location which is identified as the opening towards the Inner Earth."
https://www.infinityexplorers.com/forbidden-land-of-agartha
"Agartha is frequently associated or confused with Shamballa, which sometimes known as its capital city, and sometimes figures prominently in Vajrayana Buddhist and Tibetan Kalachakra.
There are myths and legends from all around the world that has seemed to indicate the existence of a world inside the earth."
https://desihighway.com/agartha-the-hollow-earth-theory-and-mythology/
"Buddhists believed (and still believe) that millions of people live in Agharta, an underground paradise ruled by the king of the world."
https://www.ancient-code.com/the-forbidden-land-of-agartha-the-secrets-of-the-inner-earth/
"According to an alleged diary entry written during his polar flight, Byrd came across a warm, lush climate with Mammoth-like creatures and an ancient human race that had been residing within the Earth.
His plane was commandeered mid-air and landed for him by people in the center of the Earth who intercepted his plane with saucer-shaped aircraft. Upon landing, he was met by emissaries of a civilization many assume to be the mythical Agartha. These alleged Agarthans expressed their concern about humanity’s use of atomic bombs during WWII and employed Byrd as their ambassador to return to the U.S. government and relay their sentiment."
https://www.gaia.com/article/hollow-earth-theory-is-the-subterranean-civilization-of-agartha-real
"The main continent inside the hollow earth inhabited by fifth dimensional beings. Shamballah is one of many cities here, the main openings to this world are at the polar openings explaining the fierce veil of government secrecy surrounding the poles."
https://www.urbandictionary.com/define.php?term=agartha