Scientists say a South Pacific island shown on marine charts, world maps and Google Earth does not exist.
The supposedly sizeable strip of land, named Sandy Island, is shown midway between Australia and French-governed New Caledonia.
But when scientists from the University of Sydney went to the area, they found only the blue ocean of the Coral Sea.
The phantom island has been featured in publications for at least a decade, reports the BBC.
Scientist Maria Seton, who was on the ship, said: “We wanted to check it out because the navigation charts on board the ship showed a water depth of 1,400m in that area – very deep.
“It’s on Google Earth and other maps so we went to check and there was no island. We’re really puzzled. It’s quite bizarre.
“How did it find its way onto the maps? We just don’t know, but we plan to follow up and find out.”
Australian newspapers have reported that the invisible island would sit within French territorial waters if it existed – but does not feature on French government maps.
Australia’s Hydrographic Service, which produces the country’s nautical charts, says its appearance on maps could be the result of human error, repeated down the years.