China's research icebreaker Xuelong, or Snow Dragon, sails against ice in the Antarctic Circle, Dec. 4, 2017. Xuelong has entered the Antarctic Circle as of press time. It 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 Antarctica, which is one of the key objectives of this expedition. (Xinhua/Bai Guolong)