This article was originally published November 11, 2015.

At the age of ten, Eva Mozes Kor and her twin sister Miriam were transported to Auschwitz. There Dr. Josef Mengele used the two girls along with other twins for medical experiments. Mozes Kor went on to found the CANDLES Holocaust Museum in Terre Haute, Indiana.

On January 27, 1945, four days before my eleventh birthday, Auschwitz was liberated by the Soviet army. I returned to my village in Romania to find that no one from my family other than Miriam had survived.

Forty years passed before I spoke to Miriam about our experiences in Auschwitz. She died in 1993 from the long-term effects of Mengele’s experiments. That year I was invited to lecture to some doctors in Boston and was asked if I could bring a Nazi doctor with me. I thought it was a mad request until I remembered that I’d once been in a documentary which had also featured a Dr. Hans Münch from Auschwitz, who had known Mengele. I contacted him in Germany and he agreed to meet with me for a videotaped interview. On my way to meet this Nazi doctor, I was so scared, but when I arrived at his home he treated me with the utmost respect. I asked him if he’d seen the gas chambers. He said this was a nightmare he dealt with every day of his life. I was surprised that Nazis had nightmares too and asked him if he would come with me to Auschwitz to sign a document at the ruins of the gas chambers. He agreed.

In my desperate effort to find a meaningful thank-you gift for Dr. Münch, I searched the stores, and my heart, for many months. Then the idea of a forgiveness letter came to my mind. I knew it would be a meaningful gift for Dr. Münch, but even more important, it became a gift to myself. I realized I was not a hopeless, powerless victim. When I asked a friend to check my spelling, she challenged me to forgive Mengele too. At first I was adamant that I could never do that. But with time, I realized that now it was I who had the power: the power to forgive. It was my right to use it. No one could take it away.

On January 27, 1995, at the fiftieth anniversary of the liberation of Auschwitz, I stood by the ruins of the gas chambers with my children, next to Dr. Münch and his children and grandchild. Dr. Münch signed his document about the operation of the gas chambers while I read my document of forgiveness and signed it. As I did that, I felt a burden of pain lifted from me. I was no longer in the grip of hate; I was finally free.

The day I forgave the Nazis, I also privately forgave my parents, whom I had hated all my life for not having saved me from Auschwitz. Children expect their parents to protect them; mine couldn’t. And then I forgave myself for hating my parents.

I believe with every fiber of my being that every human being has the right to live without the pain of the past. For most people there is a big obstacle to forgiveness because society expects revenge. We need to honor and remember our victims, but I always wonder if my dead loved ones would want me to live with pain and anger until the end of my life. Some survivors do not want to let go of the pain. They call me a traitor and accuse me of speaking in their name. I have never done that. Forgiveness is as personal as chemotherapy – I do it for myself.