A customs staff worker checks the customs declaration documents at the Manzhouli Customs in Manzhouli, north China's Inner Mongolia Autonomous Region, Jan. 10, 2019. Manzhouli is a major land port in north China's Inner Mongolia, with the lowest temperature of -40 degrees Celsius in winter. Customs staff workers of Manzhouli still dedicate to their jobs in such low temperature. (Xinhua/Zou Yu)