Japanese Army Unit 731 was established in 1933 and engaged in experiments on human bodies and animals, research and production of biological and chemical weapons, and other war crimes under the banners of the Ishii Corps, the Dongxiang Corps and the Kwantung Army's Epidemic Prevention and Water Purification Department. In 1936, a research and production base for biological weapons was established in Harbin's Pingfang district, and 6.1 sq km was seized as a special military area. In August 1945, most buildings in the area were destroyed by the Japanese during their escape after being defeated by the Red Army. In 2006, the site was designated a protected body of key national cultural relics by the State Council. In 2014, it was named a national 4A scenic spot.