Unit 731 victim. Image Source: Wiki.
In the past century, crimes against humanity were committed in a spirit of secular confidence. Decency - or backwardness - had once prevented certain aspects of human existence from being quantified. But in the 20th century, a perfect blend of brutality and scientific advancement swept away both decency and backwardness. During times of conflict and oppression, older prohibitions fell by the wayside. Wherever researchers and doctors worked beyond the pale, beyond scrutiny and controls, human beings were probed and experimented upon using scientific and industrial methods. War removed barriers to the quest for knowledge. This was a phenomenon of the time, a mentality which combined limitless savagery with a bizarrely searching rationality. It became a blind worship at the altar of knowledge, which had to be gathered at any cost to win victory. Indeed, one of the purposes of war in advanced societies is that conflict removes barriers to research, permitting explorations of the unthinkable. The Nazi concentration camps are the most famous examples of this phenomenon, but human experimentation occurred in other places.
Less well known but no less horrifying than the Nazi concentration camps was Unit 731, a covert Japanese research and development centre which operated during the Second Sino-Japanese War and World War II. It was located in the Pingfang district of Harbin, in the state of Manchukuo, that is, Japanese-occupied China. Officially known as the Epidemic Prevention and Water Purification Department of the Kwantung Army (関東軍防疫給水部本部 Kantōgun Bōeki Kyūsuibu Honbu), Unit 731 was the site of some of the worse war crimes in history. It was constructed between 1934 and 1939; by the fateful year 1941, it was known simply as Unit 731. The victims were mainly Chinese, with some southeast Asians, Russians and Pacific Islanders; they included infants and the elderly. Women were impregnated by rape and then became subjects of experiments along with their foetuses. Some 200,000 people died at the unit.