She was allegedly subjected to and witnessed human experimentation under Josef Mengele.
Kor founded the CANDLES ("Children of Auschwitz Nazi Deadly Lab Experiments Survivors") Holocaust Museum and Education Center in 1995 to educate the public about eugenics, the Holocaust, and the power of forgiveness. Kor received international attention when she publicly forgave the "Nazis" for what had allegedly been done to her. This story was later explored in the documentary Forgiving Dr. Mengele.
See the "External links" section regarding Holocaust revisionist criticisms.
Note that besides the external sources listed here, an alleged Holocaust confessor/witness may be extensively discussed in the external sources listed in the articles on the particular Holocaust camps and/or other Holocaust phenomena the individual is associated with.