Dozens of elderly Auschwitz survivors returned to the former Nazi concentration and extermination camp to commemorate International Holocaust Memorial Day, on the 71st anniversary of the camp's liberation by Soviet troops.

They walked through the gate that bears the notorious "Arbeit Macht Frei" (Work Makes You Free) sign and laid wreaths at a former execution site known as the "death wall". Thousands of victims were shot by firing squad at this wall, before methods of mass murder in gas chambers were introduced by the camp's Nazi German administrators.

Holocaust Memorial Day
Holocaust survivors walk under the "Arbeit Macht Frei" sign at the gates of Auschwitz-Birkenau, the former Nazi German concentration and extermination campKacper Pempel/Reuters
Holocaust Memorial Day
Survivors place candles and wreaths at the death wall at AuschwitzKacper Pempel/Reuters
Holocaust Memorial Day
Kacper Pempel/Reuters
Holocaust Memorial Day
Survivors attend a ceremony in the former Auschwitz-Birkenau concentration and extermination campKacper Pempel/Reuters
Holocaust Memorial Day
Survivor Asher Aud speaks during a memorial ceremony at the former Auschwitz-Birkenau campKacper Pempel/Reuters
Holocaust Memorial Day
Survivor Halina Brzozowska speaks during a ceremony at the former Nazi concentration and extermination campKacper Pempel/Reuters
Holocaust Memorial Day
Survivor Asher Aud speaks during a memorial ceremony at the former Auschwitz-Birkenau campKacper Pempel/Reuters
Holocaust Memorial Day
Auschwitz survivors Miroslaw Celka and Janina Reklajtis attend a ceremony in the former Nazi concentration and extermination campKacper Pempel/Reuters

"I experienced hell on this earth, I'm scared to tell. I have seen the human death, pain and suffering," one survivor, Bronislawa Czeczulowska, told Reuters, showing a tattooed inmate number on her forearm. Jerzy Kucharski, who was 15 years old when he was in the death camp, told Reuters: "The fire from the crematorium chimneys, it is still embedded in the eyes of everyone who saw it."

The theme of this year's anniversary ceremonies is "Returns" and focuses on the return to normal life by liberated survivors after the Second World War.

Holocaust Memorial Day
Kacper Pempel/Reuters
Holocaust Memorial Day
Kacper Pempel/Reuters
Holocaust Memorial Day
Flowers are placed at the death wall at the former Nazi concentration and extermination campKacper Pempel/Reuters
Holocaust Memorial Day
Portraits of victims are seen on the wall in of the barracks of the former Nazi concentration and extermination campKacper Pempel/Reuters
Holocaust Memorial Day
Notes and stones are placed into the death wallKacper Pempel/Reuters
Holocaust Memorial Day
Attendees look at some photographs during a ceremony in the former Nazi German concentration and extermination campKacper Pempel/Reuters
Holocaust Memorial Day
The Nazi slogan "Arbeit macht frei" (Work sets you free) is pictured over the gates of the former Auschwitz-Birkenau Nazi concentration and extermination campKacper Pempel/Reuters

Around 1.5 million people, mostly Jews, but also Poles, Roma, Soviet prisoners of war, homosexuals and people of other nationalities, were killed at the Nazi camp which has became a symbol of the horrors of the Holocaust.