In ancient times, the concept of a subterranean land inside the Earth appeared in mythology, folklore and legends. The idea of subterranean realms seemed arguable, and became intertwined with the concept of "places" of origin or afterlife, such as the Greek underworld, the Nordic Svartálfaheimr, the Christian Hell, and the Jewish Sheol (with details describing inner Earth in Kabalistic literature, such as the Zohar and Hesed L'Avraham). The idea of a subterranean realm is also mentioned in Tibetan Buddhism belief According to one story, there is an ancient city called Shamballa which is located inside the Earth

According to the Ancient Greeks, there were caverns under the surface which were entrances leading to the underworld, some of which were the caverns at Tainaron in Lakonia, at Troezen in Argolis, at Ephya in Thesprotia, at Herakleia in Pontos, and in Ermioni. In Thracian and Dacian legends, it is said that there are underground chambers occupied by an ancient god called Zalmoxis. In Mesopotamian religion there is a story of a man who, after traveling through the darkness of a tunnel in the mountain of "Mashu", entered a subterranean garden

Chapel, bell tower and penitential beds on Station Island. The bell tower stands on a mound that is the site of a cave which, according to various myths, is an entrance to a place of purgatory inside the Earth. The cave has been closed since October 25, 1632. In Celtic mythology there is a legend of a cave called "Cruachan," also known as "Ireland's gate to Hell," a mythical and ancient cave from which according to legend strange creatures would emerge and be seen on the surface of the Earth There are also stories of medieval knights and saints who went on pilgrimages to a cave located in Station Island, County Donegal in Ireland, where they made journeys inside the Earth into a place of purgatory In County Down, Northern Ireland there is a myth which says tunnels lead to the land of the subterranean Tuatha Dé Danann, a group of people who are believed to have introduced Druidism to Ireland, and then went back underground

In Hindu mythology, the underworld is referred to as Patala. In the Hindu epic Ramayana, it has been depicted how Rama and Lakshmana were taken by the king of the underworld Ahiravan, brother of the demon king Ravana. Later on they were rescued by Hanuman. The Angami Naga tribes of India claim that their ancestors emerged in ancient times from a subterranean land inside the Earth The Taino from Cuba believe their ancestors emerged in ancient times from two caves in a mountain underground.

Natives of the Trobriand Islands believe that their ancestors had come from a subterranean land through a cavern hole called "Obukula". Mexican folklore also tells of a cave in a mountain five miles south of Ojinaga, and that Mexico is possessed by devilish creatures who came from inside the Earth.

In the middle ages, an ancient German myth held that some mountains located between Eisenach and Gin Germany hold a portal to the inner Earth. A Russian legend says the Samoyeds, an ancient Siberian tribe, traveled to an underground cavern city to live inside the Earth. The Italian writer Dante describes a hollow earth in his well-known 14th century work Inferno, in which the fall of Lucifer from heaven caused an enormous funnel to appear in a previously solid and spherical earth, as well as an enormous mountain opposite it, "Purgatory".

In Native American mythology, it is said that the ancestors of the Mandan people in ancient times emerged from a subterranean land through a cave at the north side of the Missouri River. There is also a tale about a tunnel in the San Carlos Apache Indian Reservation in Arizona near Cedar Creek which is said to lead inside the Earth to a land inhabited by a mysterious tribe. It is also the belief of the tribes of the Iroquois that their ancient ancestors emerged from a subterranean world inside the Earth. The elders of the Hopi people believe that a Sipapu entrance in the Grand Canyon exists which leads to the underworld.

Brazilian Indians, who live alongside the Parima River in Brazil, claim that their forefathers emerged in ancient times from an underground land, and that many of their ancestors still remained inside the Earth. Ancestors of the Inca supposedly came from underground caves which are located east of Cuzco, Peru.