They insist the snaps show what appear to be the ruins of a city that could pre-date Egypt's pyramids, which appeared after 2600BC.
They told a French newspaper that one of the structures appears to be a pyramid. Now the anonymous group wants to raise funds to explore the secret location where the images were taken.
They would not reveal the exact location, however, saying only that it was somewhere in the Caribbean Sea. The claims have raised eyebrows on the internet, though sceptics refrained from debunking them entirely - just in case.
The legend of Atlantis, a city of astonishing wealth, knowledge and power that sank beneath the ocean waves, has fascinated millions.
Time and time again hopes have been raised that the lost city has been found - only for those hopes to be dashed against the evidence (or lack thereof). Its location - or at least the source of the legend - remained a tantalising mystery.
In 1997, Russian scientists claimed to have found Atlantis 100 miles off Land's End.
In 2000 a ruined town was found under 300ft of water off the north coast of Turkey in the Black Sea.
The area is thought to have been swamped by a great flood around 5000BC, possibly the floods referred to in the Old Testament.
In 2004 an American architect used sonar to reveal man-made walls a mile deep in the Mediterranean between Cyprus and Syria.
In 2007 Swedish researchers claimed the city lay on the Dogger Bank in the North Sea, which was submerged in the Bronze Age.
And as recently as February of this year, what appeared to be grid-like lines that resembled city streets were spotted on Google Earth - in the ocean off the coast of Africa.
Sadly Google itself quickly debunked the suggestion, explaining that the lines were left by a boat as it collected data for the application.
'Bathymetric (sea-floor) data is often collected from boats using sonar to take measurements of the sea-floor,' a spokesman said.
'The lines reflect the path of the boat as it gathers the data.'
What is Atlantis?
Atlantis was first described by the Greek philosopher Plato more than 2,000 years ago. In 360 BC, Plato wrote that Atlantis was a major sea power located in the Atlantic, larger than ancient Libya and Asia Minor (modern Turkey) put together, and was ‘the way to the other islands, and from these you might pass to the whole of the opposite continent'.
Plato's account included detailed descriptions of the island – with mountains in the north and along the coast and a plain in the south. It kings were said to be descendants of Poseidon, the god of sea, but their divine lineage became diluted as they mixed with mortals.
By around 9600 BC, the island had conquered much of western Europe and Africa and enslaved its enemies. This date would make the city nearly as old as the end of the last ice age and pre-dates the earliest recorded city states, found in what is now Iraw. After a failed attempt to invade Athens, the entire island sank into the sea ‘in a single day and night of misfortune'. One of the most plausible theories is that Plato was describing the Minoan civilisation on Crete and the neighbouring island of Santorini which was devastated by volcanic eruption around 1600 BC.
