(251231) -- HARBIN, Dec. 31, 2025 (Xinhua) -- This photo taken on Dec. 31, 2025 shows documentary material on display at a special exhibition of social donation of cultural relics and historical materials at the Exhibition Hall of Evidence of Crimes Committed by Unit 731 of the Japanese Imperial Army in Harbin, capital of northeast China's Heilongjiang Province. The opening ceremony of the special exhibition was held here on Wednesday. (Xinhua/Zhang Tao)