HANGZHOU, Dec. 20 (Xinhua) -- A huge pile of carbonized unhusked rice dating back 5,000 years was found in the ruins of ancient Liangzhu City in eastern China's Zhejiang Province.

The pile was about 60 cm thick and covered about 5,000 square meters, the provincial institute of archaeology said Wednesday. The pile stored about 100,000 kg of carbonized rice.

Liu Bin, head of the institute, said grain storage was an important symbol of city, and the discovery demonstrated that Liangzhu had a relatively developed paddy agriculture.

The ancient city of Liangzhu was discovered in 2007 in Hangzhou's Yuhang District. In 2015, archaeologists found a large water project while excavating the neolithic remains of the city. It is believed to be the world's earliest water conservation system.