A file photo of Zhoukouidian fossil site. [File photo]

Fossils of Peking Man were discovered in the 1920s, including an entire cranium that earned Zhoukoudian fame as one of the birth places of humans. Ashes, burned bones and rocks, as well as charred seeds were also found in 1929, according to Gao, leading many archeologists to agree that Peking Man knew how to use fire.

However, there has always been skepticism that they resulted from natural fire. "The evidence this time is more convincing," Gao said, "It has been found under the earth untouched, without weather damage."