The legend of the underwater city of Atlantis lives on - but the mystery of five other lost worlds have also been revealed.
There are no doubt many cities and lands lost forever to time and some of them may never have even existed in the first place.
Atlantis, for example, is one of the most famous lost worlds and despite most people believing the underwater city to be the stuff of myths and legends, it hasn't stopped archaeologists searching for it.
Below is look at the story behind Atlantis as well as five other lost worlds that continue to fascinate the public today - see what you make of them.
Atlantis
This island was first mentioned in Greek philosopher Plato's 'Timaeus' and 'Critias' works around the 4th century BC.
The land was a utopian civilisation created by half-humans and half-gods and used by Plato as an allegory to represent arrogance.
Atlantis launched an attack on Athens, reports The Portalist , who then retaliated with brute force, burning it down until it collapsed in on itself from earthquakes.
The gods turned their back on it and eventually the island sank to the bottom of the ocean.
Some scholars have argued that the story was based on real-life events and theories as to where Atlantis now is range from somewhere off the coast of Spain to Antarctica.
Lemuria
Legend has it that this place was once a continent south of Sri Lanka in the Indian Ocean.
The fascination with Lemuria is largely down to British zoologist Philip Sclater who in the 19th century was stumped over the lemurs of Madagascar.
He claimed that there were many more lemurs in Madagascar than anywhere else in the world and concluded that what allowed the mammals to migrate must have been a now-sunken continent, which he called Lemuria.
However, the supercontinent of Pangea some 300million years ago that eventually broke up is a more likely explanation for Sclater's theory.
Ys
This city - also known as Ker Ys or Is - is said to have been located in Douarnenez Bay in Brittany, France.
Ys was famous all over the world for its beautiful gardens and buildings and was a wealthy trading hub where citizens lived comfortably.
The Breton legend goes that the place was founded after Dahut, a magician and the daughter of Gradlon, King of Kerne, begged with her father to build a city by the sea.
Unfortunately, Dahut allowed a passing handsome knight to enter through the city gates after giving him the keys.
The knight turned out to be the Devil in disguise and he left the city gates open. allowing the ravaging sea to enter and drown the land.
Dahut was eventually turned into a mermaid who lured sailors to their death.
Thule
A land thought to be located at the ends of the Earth - or even slightly north of the Orkney Islands - and one of its first mention was by Greek explorer Pytheas.
He described the place as somewhere were land and sea are blurred together, referring to its consistency as like a "jellyfish".
Large sea monsters surrounded the land and Thule citizen's painted themselves blue when they rode into battle on chariots.
They made their homes from whale bones and kept warm with seal-skin clothing.
Modern cartographers believe that Thule, if it existed, was most likely somewhere around Norway or Iceland.
Like many lost worlds, some think that it was eventually swallowed up by the sea.
Iram of the Pillars
This land is sometimes called ‘Atlantis of the Sands’ and was eventually destroyed, as described in the Al-Fajr, the 89th chapter of the Qu’ran.
The once thriving metropolis was home to people called Ad, who were said to turn away from the word of Allah and led disreputable lives.
Much like the story of Sodom and Gomorrah in the Bible, the city was wiped out in response to its citizens' behaviour.
A sandstorm rose and swept the place for up to eight days, swallowing it up and leaving nothing but desert.
Some people believe that the ancient city of Ubar in Oman, which was only re-discovered in the 1990s, is actually the Iram of the Pillars.
Agartha
The deepest lost world on the list is Agartha (or Agarthi), which is believed to be located inside the Earth’s core.
Believers of this underworld are called ‘Hollow-Eathers’ because they see the Earth’s core as hollow and containing a civilisation and many cities.
A hidden entrance is thought to be somewhere on the Gobi Desert and built using such advanced technology by Agarthans that humans on the surface wouldn’t be able to locate it.
The capital city inside is called Shambala with a “smoky” sun at the centre providing light to all its inhabitants.
