Photo taken aboard Tianjian on Sept. 20, 2017 shows aurora in the waters of Norwegian Sea. Tianjian, a multi-function cargo ship of China, left the waters of Barents Sea on Sept. 19 (Beijing time) and sailed into the waters of Norwegian Sea. Tianjian is one of China's planned six cargo ships to ply the Arctic passage to Europe in 2017. (Xinhua/Liu Shiping)