Motti Alon was deported to the Auschwitz concentration camp in Nazi-occupied Poland from Budapest in 1944 as a child, with his twin brother and their mother.

He recalls seeing camp physician Josef Mengele - known for performing medical experiments on prisoners - forcing a dwarf, suffering from quadriplegia, to have sex with a Roma woman.

Watch more about how Josef Mengele experimented on twins at Auschwitz online at BBC Newsnight, or on BBC World News at 23:30 GMT on Friday 30 January.