People have fun at the Wusi Square in Qingdao, East China's Shandong province, April 30, 2018. The coastal city will host the 18th summit of the Shanghai Cooperation Organization (SCO) in June. [Photo/Xinhua]

Aerial photo taken on May 4, 2018 shows the Zhanqiao Pier and the Qingdao Bay in Qingdao, East China's Shandong province. The coastal city will host the 18th summit of the Shanghai Cooperation Organization (SCO) in June. [Photo/Xinhua]

Photo taken on May 23, 2018 shows a view of Qingdao, East China's Shandong province. The coastal city will host the 18th summit of the Shanghai Cooperation Organization (SCO) in June. [Photo/Xinhua]