Ice mailbox installed at Harbin Ice-Snow World

Mailmen ride on a snow sledge after collecting letters and postcards from an ice mailbox of China Post at Harbin Ice-Snow World in Harbin, northeast China's Heilongjiang Province, Jan. 23, 2018. The mailbox made of ice with the height of 2.6 meters was installed at Harbin Ice-Snow World for tourists.(Xinhua/Wang Jianwei)