Twins at Auschwitz were afforded slight privileges over the other children. They weren't killed. They kept their own hair. They didn't have to wear the striped uniform. They were fed a tiny bit more.

On the flip side, they were used as human subjects in the laboratory of Dr Josef Mengele. It is believed that Dr Mengele was looking for the key to producing twins in any pregnancy, in order to swiftly swell the Master Race. But in reality, he did whatever whim took him at the time.

Eva personally witnessed such atrocities as two Roma twins stitched together, back to back, in a bid to artificially create Siamese twins. The unfortunate girls lay screaming for three days, before gangrene set in and they died.

She and Miriam understood early on that the norm was for one twin to be experimented upon, while the other was used as a control subject. If anybody died, their twin was immediately killed too. In that way, joint autopsies could show what had (if anything) been changed in the tests.

Their time at Auschwitz was marked by a bitter determination that both should survive against the odds. That was naturally a difficult feat to pull off in the circumstances.

On one occasion, Eva was given five injections, which caused a soaring temperature. When Dr Mengele examined her, he commented, "It's a shame. She's so young, but she'll be dead within two weeks."

She was given neither food, drink nor medicine. But Eva learned that there was a tap at the end of the ward. She forced herself out of bed and crawled, losing consciousness often, to reach the life-saving water. Eva was also assisted once by a nurse, who smuggled in a small piece of birthday cake.

Using subterfuge with the thermometer, Eva was able to convince Mengele that her fever had broken. After it was left under her arm, she would remove the thermometer until the reading fell, then push it down enough to stick out on the other side of her arm.

He let her return to the barracks after two weeks, where she was able to get more help to recover.

The procedures performed on her sister Miriam left her with kidneys the size of a ten year old. In later life, Eva would donate one of her own in order to save her twin's life again. Unfortunately, Miriam contracted a rare form of cancer - also believed to be linked to those childhood experiments - which eventually took her life in 1993.

But on January 27th 1945, when the Russians entered Auschwitz to inform its inhabitants that they were now free, Eva and Miriam Mozes were there to receive them. It's that moment which Holocaust Memorial Day marks.

Eva Mozes Kor speaks to Wizzley today, as just one of the events occurring internationally, raising awareness of all that happened there in a bid to stop it ever happening again.