Southwest China's Sichuan Province launched its largest ever archaeological excavation project Tuesday, according to the Sichuan Provincial Cultural Archaeology Research Institute.

The excavation project, which is called Wudongde Hydropower Station Cultural Relics Protection Project, will be carried out in Huidong and Huili counties in Liangshan Yi Autonomous Prefecture.

Preliminary excavation has discovered 21 cultural relics sites, including one site above the ground and 20 underground. The sites are from between the Neolithic Age and the Qing Dynasty.

Among the underground sites, 13 date from between the Neolithic Age and Warring States periods, and seven are from between the Ming and Qing dynasties.

Stone implements, stone burial areas and pottery have also been unearthed during preliminary excavation.

The excavation area covers 134,000 square meters, and is expected to be completed in 2021. A total of 270 million yuan (40.7 million U.S. dollars) will be invested in the project.