Chinese archaeologists have discovered a 700-year-old rare moat surrounding a monastery in southwest China's Tibet Autonomous Region.

"The unearthed part of the moat whirled its way about every five meters in a square manner, which has been a shape rarely found in history both at home and abroad," said Zhang Jianlin, deputy director of the Shaanxi Archeology and Research Institute.

The excavated section of the river way is 8.8 meters deep, 6 meters and 3.3 meters wide on its upside and downside respectively, said Zhang, who took charge of the excavation work.

The moat is 17 meters far from the Sagya Monastery in Sagya County, Xigaze City in the southern part of Tibet. The monastery was built in the 13th century when the county was a political and religious center for the region.

"This kind of moat was recorded in the local historical data and I also heard about it from the elders," said Bandian Toinyu, director with the management committee of the monastery. "But I have never seen such moat before."

The whirling moat looked beautiful and might be helpful for defense in wartime, according to Bandian Toinyu.

The Sagya Monastery covers an area of 14,700 square meters. The building began to be restored in 2002 at a cost of 86 million yuan (10 million U.S. dollars). The renovation is expected to complete at the end of this year.