Members of a Japanese medical delegation mourn for Unit 731 victims in Harbin, capital of northeast China's Heilongjiang Province, May 4, 2014. A Japanese medical delegation visited the site of Unit 731, a Japanese biological and chemical warfare research troop during World War II, Sunday in Harbin. The visit was intended to investigate on Japanese medical war crimes during WWII. Takeshi Yoshinaka, director of the Kyoto Min-iren Chuo Hospital and a delegation member, said Unit 731 war crimes such as germ warfare should be admitted by Japan's medical community. Unit 731 members conducted a series of human experiments which subjected victims to vivisections, germ war attacks, weapon tests and other forms of torture. [Photo by Wang Kai/Xinhua]