China's research icebreaker Xuelong, or Snow Dragon, sails against ice on its way to Zhongshan station in Antarctic, Dec. 20, 2017. Xuelong set sail from Shanghai, east China, on Nov. 8, beginning the country's 34th Antarctic expedition. Researchers will conduct preliminary work on China's fifth station in the Antarctic, which is one of the key objectives of this expedition. (Xinhua/Bai Guolong)