Unit 731
Nation Involved: Japan
Time Period: 1937 to 1945
The Imperial Japanese Armed Forces did some horrible things. Yet perhaps the worst of them all was the experiments they conducted on people at the Unit 731 facility. This unit committed more human rights violations and war crimes than any other nation in modern history. The scientists studied various diseases to see how a person reacted to them, including things like syphilis. To make sure they were given various STDs, prisoners were often raped by the guards. Plus, they did not just test a few men here and there.
They experimented on women and children, including pregnant women. Several were forced to do vivisections, which opened them up internally for examination. By the way, none were given anesthesia for this. Unit 731 also tested out chemical weapons, as you can imagine. On top of this, they tested out regular weapons including grenades and flamethrowers to see how they worked on human targets. They also deliberately watched people starve to death. Funny enough, the U.S. gave them immunity after World War II in exchange for all the data these evil people collected in their experiments.