Bulgarian archaeologists claimed to have found evidence of brain surgery performed by ancient humankind, allheadlinenews.com reported.
Georgi Nehrizov, who led excavations near Bulgarias town of Svilengrad, said that he had found a 4000-year-old skull with a perfectly made hole.
The hole was obviously made for medical reasons, Nehrizov said.
The skull dated back to the Thracian times in what is now Bulgarian territory. It was the first such find from that period.
The Thracians lived on the Balkan peninsula from about 3500 BCE to the first century CE. Orpheus and Spartacus are said to have been Thracians.
Bulgarian archaeologists have made a series of finds of Thracian gold and silver objects.
A collection of Thracian gold treasures is travelling around the world, rousing immense interest.
