Lost lands can be continents, islands or other regions supposedly existing during prehistory, having since disappeared as a result of catastrophic geological phenomena or slowly rising sea levels since the end of the last Ice Age. Lost lands, where they existed, are supposed to have subsided into the sea, leaving behind only a few traces or legends. The term can also be extended to mythological lands generally, to underground civilizations, or even to whole planets.
The classification of lost lands as continents, islands, or other regions is in some cases subjective; for example, Atlantis is variously described as either a "lost island" or a "lost continent". Lost land theories may originate in mythology or philosophy, or in scholarly or scientific theories, such as catastrophic theories of geology.
As the study "Lost Continents" by L. Sprague de Camp seeks to show, many modern writers speculate about ancient civilizations that dwelled on continents now deluged under sea level. According to de Camp, there is no real scientific evidence for any lost continents whatsoever.
- The most famous lost continent is Atlantis. Atlantis, like Hyperborea and Thule, is ultimately derived from ancient Greek geographic speculation.
- The name of hypothetical vanished continent Mu originated from the first attempted translation of the Madrid Codex, one of only four remaining Maya codices.
- Something similar seems to have happened upon the discovery of the Sanskrit literature by Europeans. Louis Jacolliot claimed to have learned from this literature about a sunken continent called Rutas. This in turn seems to have influenced Madame Blavatsky and her speculations about Lemuria. Speculations about Kumari Kandam also seem to be linked to this field. The name Lemuria originated from the hypothesis about a land bridge between India and South Africa.
Other lost lands
In addition to these myths about lost continents there also are various regional legends about lost lands; see e.g. Lyonesse, Cantref Gwaelod (also known as Lowland Hundred), or the legend about Lomea, located at the Goodwin Sands. Unlike the lost continents mentioned above, whose location has been a matter of speculation, these lost lands are associated with specified places.
It is likely that until relatively recent times the Isles of Scilly, with which Lyonesse is often associated, were much larger, many of them being joined into a single island named Ennor. Rising sea levels flooded the central plain around 400–500 AD, forming the current islands.
Although the existence of lost continents in the above sense is mythical, there are some places on earth that were once dry land but are now submerged under the sea. Approximately listed by size, these are:
- Sundaland, the now submerged Sunda Shelf.
- Zealandia, a continent that is now 93% submerged under the Pacific Ocean.
- Kerguelen Plateau, a submerged micro-continent which is now 1–2 km below sea level.
- Beringia, connecting Asia and North America.
- Doggerland, the bed of the North Sea, inundated by rising sea level during the Holocene.
- The bed of the Persian Gulf.
- A large island in the Mediterranean Sea, of which the Maltese Islands are the only parts not now submerged.
- Maui Nui, once a large island of the Hawaii archipelago; several major islands represent residual high ground of Maui Nui.
- Verdronken Land van Reimerswaal, most of this region in The Netherlands vanished in a storm in 1532; the town of Reimerswaal survived as an island into the 17th century; the last bits of land vanished in the early 19th century.
- Strand, an island off the German coast with the town Rungholt, eroded away by storm surges before being washed away by a final flood in 1634.
- Jordsand, once an island off the Danish coast, eroded away by storm surges before being washed away by a final flood between 1998 and 1999.
- Ferdinandea, submerged volcanic island which has appeared at least four times in the past.
- Sarah Ann Island, now submerged guano island, located just north of the equator. Vanished between 1917 and 1932.
- Ravenser Odd, a large 13th century town on the old sandbank promontory in East Yorkshire, which became an island and then vanished in January 1392.
- Buyan, an island with the ability to appear and disappear in Russian mythology
- Shangri-La, a fictitious valley in Tibet the idea of which may have been inspired by the myth of Shambhala
- Quivira and Cibola, also known as the Seven Cities of Gold. These were suspected somewhere in America by the Conquistadors.
- El Dorado, mythic city of gold.
- Lemuria (continent)
- Mu (lost continent)
- Ys; a mythical city built on the coast of Brittany, and later swallowed by the ocean. Most versions of the legend place the city in the Baie de Douarnenez.
- Cantre'r Gwaelod is the legendary ancient sunken realm said to have occupied a tract of fertile land lying between Ramsey Island and Bardsey Island in what is now Cardigan Bay to the west of Wales.
Phantom islands, as opposed to lost lands, are land masses formerly believed by cartographers to exist in the historical age, but to have been discredited as a result of expanding geographic knowledge. Terra Australis is a phantom continent. While a few phantom islands originated from literary works (an example is Ogygia from Homer's Odyssey), most phantom islands are the result of navigational errors.
Hollow Earth theory
Also related to the theme of Lost lands is that of Hollow Earth, as some proponents of Hollow Earth theory have claimed that the inner earth would be inhabited. Furthermore, using the concept of vast underground caves or even a completely Hollow Earth, some authors try to explain how an ancient civilization could continue to exist, even if its former continent became deluged.
The most prominent lost land mentioned in Hollow Earth theory would be Agartha.
Accounts of a Hollow Earth
Some of these authors, such as H.P. Blavatsky and theosophist followers, believed in the existence of a number of lost lands within the Hollow Earth and held many "fictional" accounts of these places and their peoples to be true. Such accounts include:
- The Coming Race by Edward Bulwer-Lytton, published in 1871.
- Mission de l'Inde en Europeä by Alexandre Saint-Yves d'Alveydre, published in 1886.
- The Phantom of the Poles by William Reed, published in 1906.
- The Smoky God by Willis Emerson, published in 1908.
- Agartha – Secrets of the Subterranean Cities
- Journey to the Earth's Interior by Marshall B. Gardner, published in 1913.
- Le Roi du Monde by René Guénon, published in 1924.
- Beast, Men and Gods by Ferdinand Ossendowski Published in 1931.
- Amazing Stories magazine, which, beginning in 1943, published a plethora of material by Richard Shaver and Raymond A. Palmer, detailing Shaver's experiences with the inhabitants of the Hollow Earth.
- The Hollow Earth, by Raymond W. Bernard.
- Flying Saucers from the Earth's Interior, by Raymond W. Bernard.
- Agharta – The Subterranean World by Dr. Raymond Bernard.
- Nazisme et sociétés Secrètes by Jean-Claude Frère, published in 1974.
- World Beyond the Poles by Giannini.
- Paradise Found by William F. Warren.
- A recurring element in Sanctuary (TV series)
Diverse expeditions at diverse epochs and lands, have tried to find proof of the existence of a subterranean world, from the Col. Fawcett notorious expeditions  to Third Reich sponsored attempts and many private expeditions in modern times, some sponsored by cultural foundations and even magazines as the 1978 Roncador Expedition to the Roncador mountains in Matto Grosso, Brazil, sponsored by the magazine Noticias from Uruguay and led by pilot and writer A. de Souza. None have returned positive results.
Similar to the theme of lost continents is the theme of lost planets, planets thought to have existed during prehistory only to be later destroyed by a global cataclysm. The disruption theory of the formation of the asteroid belt from a hypothetical fifth planet has given birth to a number of these, including the doomed Phaeton, Tiamat, and the apocalypse bringer Nibiru. Others such as Planet V, Theia, Planet X and Vulcan arose to explain irregularities in planetary phenomena.
In literature and philosophy
The following individuals are known for having written on the subject of lost lands:
- H.P. Blavatsky
- Edgar Rice Burroughs
- William L. Chester, (Nato'wa, Kioga book series)
- James Churchward
- Ignatius L. Donnelly
- Arthur Conan Doyle, (The Lost World)
- Burak Eldem
- Warren Ellis
- Philip José Farmer
- James Gurney(Dinotopia)
- H Rider Haggard
- Robert A. Heinlein in his novelette Lost Legacy
- James Hilton, (Lost Horizon)
- H. P. Lovecraft often invoked the names of lost lands of his own invention, a practice that subsequently gave birth to the Cthulhu mythos.
- Augustus Le Plongeon
- Zecharia Sitchin
- Samael Aun Weor
- J. R. R. Tolkien, (Middle-earth)
- Jack Vance describing the Elder Isles in his Lyonesse Trilogy
- Jules Verne used the idea of a partially hollow Earth in his 1864 novel, A Journey to the Center of the Earth.
- Lost lands figured prominently in the philosophy of the Nazi Thule society in regards to researchers of the occult and Nazi mysticism such as Karl Maria Wiligut, Heinrich Himmler and Otto Rahn.
- A lost land (possibly the Garden of Eden) found at the center of the Earth is the site of the climatic battle between Godzilla and Biollante in the novel Godzilla at World's End by Marc Cerasini.
- Maclellan, Allan (1982). The Lost World of Agharti. Guernsey CI, U.K.: Souvenir Press. pp. 141–143. ISBN 0-285-63314-7.
- Maclellan, Allan (1982). The Lost World of Agharti. Guernsey CI, U.K.: Souvenir Press. pp. 111–115. ISBN 0-285-63314-7.
- "Expediciôn al centro de la Tierra". Noticias. Año/Year II (36) (Montevideo, Uruguay). Sep 1978. pp. 14–27
- L. Sprague de Camp and Willy Ley, Lands Beyond, Rinehart & Co., New York, 1952.
- L. Sprague de Camp, Lost Continents: The Atlantis Theme in History, Science, and Literature, Dover Publications, 1970.
- Raymond H. Ramsay, No Longer on the Map: Discovering Places that Never Were, Ballantine, 1972.