During a high-resolution mapping of the seafloor surrounding Sicily, researchers discovered an ancient treasure: a stone monolith spanning 39 feet, resting on the bottom of the Mediterranean.
Stunned, the researchers sent down divers with cameras and video recorders to get a closer look at the monolith, which had broken into two parts. They dove 131 feet underwater in an area called the Pantelleria Vecchia Bank, located about 37 miles south of Sicily.
Several features suggest the monolith was man-made, possibly by people living during the Mesolithic period about 10,000 years ago, Lodolo said. It has a fairly regular shape and contains three holes with similar diameters. One hole, with a diameter of 24 inches, punched all the way through the stone.
"There are no reasonable known natural processes that may produce these elements," the researchers wrote in the study, referring to the regular shape and similar size of the holes.
The Last Glacial Maximum began about 19,000 years ago, the researchers said. At that time, Europe was about 40 percent larger than it is now, but as the glaciers melted, sea levels rose about 410 feet from then until present day, Lodolo told Live Science.