Greek philosopher Plato spoke of a great lost continent in the Atlantic, swallowed by the ocean 12,000 years ago, and now researchers from Brazil and Japan say they have found one.
The catch is it probably sunk more than 50 million years ago, long before humans walked the earth, let alone the Greeks.
The Brazilian Geological Service says it has found granite and quartz on the seabed, 2.5km deep, 1450km off the coast of Rio de Janeiro. The finding suggests the area was once dry land.
"It is unusual because it is granite rock," says geologist director Roberto Ventura Santos, "and you don’t find granite on the seabed. It is more usual to find it on the mainland."
Researchers say it was once part of a large island or continental crust attached to Pangaea, a supercontinent which formed about 300 million years ago as a result of continental drift.
"This could be Brazil’s Atlantis," says Dr Santos. "We are almost certain, but we need to strengthen this hypothesis."
The Brazilian Geological Service, the Oceanographic Institute of the University of Sao Paulo and the Japan Agency for Marine-Earth Science and Technology plan to study the area further in the near future.
One thing they don't expect to find, however, is remnants of an advanced ancient civilisation, as Plato described.
"We speak of Atlantis more in terms of symbolism," says Dr Santos. "Obviously, we don’t expect to find a lost city in the middle of the Atlantic."