January 27th is International Holocaust Remembrance Day -- a day to commemorate the Nazi genocide of the second world war, in which more than six million people perished across central Europe. About a quarter of them were killed at Auschwitz in Poland. Every year, hundreds of thousands of people from all around the world visit the site of the concentration camp to remember the victims and learn more about the suffering. Tonight, we hear from an Auschwitz survivor, who recalls for us some of his painful memories. CGTN's Chuck Tinte has more.

Waclaw Dlugoborski shows his tattoo. They're a series of prisoner numbers he got upon his arrival at Auschwitz in 1943. A mark that has scarred his life forever.

WACLAW DLUGOBORSKI AUSCHWITZ SURVIVOR "At the beginning, for the first two months, there was hunger because we did not have the parcels of food I later received from my parents. People were really, really dying of hunger."

Dlugborski was initially tasked with constructing a road and carrying heavy stones for four kilometers until he was finally designated as a paramedic in the camp's hospital. It was there he witnessed the real horror of the Nazis, including a doctor carrying out inhumane medical tests.

WACLAW DLUGOBORSKI AUSCHWITZ SURVIVOR "The experiments were carried out without any rules. Apparently there was an incident when two sisters were sewn together. I did not see it, but it was said the twin sisters were stitched together. It was terrible for us and we could not understand how those doctors could do anything like that. Because, as before, there were Polish doctors, they told us what was happening, how they did it, these Polish doctors did their best to help us, and there were German doctors who did everything to destroy those prisoners."

The then 18-year-old managed to escape the camp with some of his fellow in-mates. Two days later, Auschwitz was liberated by the Red Army. Chuck Tinte, CGTN.