Reinforcement project of ruins at Yuanmingyuan starts

Staff members clean up weeds at ruins of Yuanying Guan (Immense Ocean Observatory) at Yuanmingyuan in Beijing, capital of China, May 23, 2018. The four-month reinforcement project of ruins of Immense Ocean Observatory at the historical site of Yuanmingyuan started lately.(Xinhua/Luo Xiaoguang)