A large mass of granite has been found on the seabed off the coast of Rio de Janeiro, suggesting a continent may have existed in the Atlantic Ocean, the Japan Agency for Marine-Earth Science and Technology and the Brazilian government announced.

A Brazilian official said the discovery of the granite — which normally forms only on dry land — is strong evidence that a continent used to exist in the area where the legendary island of Atlantis, mentioned in antiquity by Plato in his philosophical dialogues, was supposedly located.

According to legend, the island, host to a highly developed civilization, sunk into the sea around 12,000 years ago. No trace of it has ever been found.