It was first described by Plato in 330 BC, and now Atlantis may have finally been found.
In a new documentary, experts from Merlin Burrows, a land and sea search team based in Harrogate, claim that they have discovered the ruins of Atlantis off the coast of Spain.
Using data from commercial satellites, researchers believe that the lost city could be in Spain's Doñana National Park.
Speaking to Live Science, Bruce Blackburn, CEO of Merlin Burrows, said: "Obviously, it's a very bold thing to say.
"Everybody will have to [one of] two opinions. One is that 'This is great. Let's have a look at it, 'and one will be' That's a load of rubbish. '"
The researchers focused on Spain having read two of Plato's dialogues on Atlantis.
Mr Blackburn explained: "The Atlantis cities, which are very detailed in Plato's writing, are really there for everyone to see."
The findings will be revealed in an upcoming documentary called Atlantica – though it is unclear when this will air.
However, not everyone is so convinced that this is really Atlantis.
Speaking to Live Science, Professor Ken Feder, an expert in anthropology at the Central Connecticut State University, said: "Bless their hearts – if they're correct about this, that would be awesome.
"But here's my problem: As an archeologist, I know that I always need to be in the company of my bulls ** t detector.
"And these guys, they've done just about everything they possibly can to set off my bulls ** t detector."