Aerial photo shows workers collecting ice from the Songhua River in Harbin, capital of northeast China's Heilongjiang Province, Dec. 11, 2019. Harbin Ice-snow World, China's largest ice and snow theme park, opened for its 21st winter season on Monday in Harbin. Since Dec. 7, 2019, constructors had been preparing for the grand event and finally created a fairyland like ice world for the visitors from home and abroad. (Xinhua/Xie Jianfei)