Lost lands can be continents, islands or other regions 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.
Although the existence of lost continents in the above sense is mythical, there were many places on earth that were once dry land but submerged after the ice age around 10,000 BCE due to rising sea levels, and possibly were the basis for neolithic and bronze ageflood myths. Some others were lost due to coastal erosion or volcanic eruptions. Approximately listed by size, these are:
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 an old sandbank promontory in East Yorkshire, which became an island and then vanished in January 1392.
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.
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.[original research?] 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.