In Lingjiatan, Hanshan County of Anhui Province in China, archaeologists have discovered a primitive tribal site that was inhabited 5,000 years ago.
Remarkably advanced drilling technology and the world's earliest stone drill bits were found at the site.
Archaeology professor Zhang Jingguo said there are still many mysteries in the Lingjiatan ruins waiting to be solved.
The Lingjiatan ruins are located in Lingjiatan Village, Tongzha Township of Hanshan County in Chaohu City, Anhui Province, covering about 1.5 million square meters. Archaeologists say the 5,000 year old city was probably a prosperous city with developed construction, animal husbandry and handicrafts.
Prior to the discovery of the Lingjiatan ruins, the oldest city in China acknowledged by archaeologists was in Dantu Village in Wulian County at Rizhao City, Shandong Province, which was built more than 4,000 years ago.
In the fall of 1985, a Lingjiatan villager by the name of Wan Chuancang found jade rings, stone axes and stone chisels when digging a grave for his mother. That was the beginning of the discovery of these most important ruins of the late Neolithic Age.
From 1987 to 2000, archaeologists performed four archaeological excavations at the site. They discovered more than 1,200 pieces of precious artifacts including: an altar, 66 graves, refined jade, stoneware and pottery dating back to the late Neolithic Age.
Among these are the earliest Jade Dragon and the largest stone shovel discovered in China to date.
Archaeologists believe that 5,000 years ago, the area was highly developed, supporting the theory that Chaohu Lake Basin was a significant birthplace of Chinese culture. Among catalogued pre-historic ruins, Lingjiatan has the most jade pieces.
Professor Zhang Jingguo and his colleagues inspected these jade pieces with a stereomicroscope to research the jade treatment technology of that day.
Under 50 times magnification, they found a little hole on the back of a jade statue.
The diameter of the hole is only 0.15 millimeters. This would have required a drill with a diameter slightly thicker than a strand of hair.
At that time, before metal was used for tools, the people in Lingjiatan, 5,000 years ago, already utilized such advanced technology.
Archaeologists also found a drill bit made of stone; it is wide at the top and narrow at the bottom with drills on both ends. This drill is screw shaped, indicating that the people in Lingjiatan knew about rotary power and centrifugal force. Their knowledge of physics, mathematics, geometry, and mechanics appears to have been quite developed
Many eminent archaeologists are surprised at how advanced the stone drill was.
Archaeologists also discovered huge stone relics as high as 10 meters (33 ft.) at Lingjiatan; built more than 1,000 years earlier than Britain's Stonehenge.
Five thousand years ago, people of Lingjiatan should only have been using stone and wood tools; it is unknown how they cut and transported such huge and heavy stones.