As the world remembers the Nazi crimes at Auschwitz, a Welsh soldier imprisoned at the camp recalls the full horror of what he witnessed.
Charlie Evans was one of 500 British prisoners of war sent to work next to the extermination camp in Poland.
Mr Evans, from Presteigne in Powys, said soldiers - who were themselves starved and savagely beaten - looked on helplessly as the terror unfolded.
Sixty years on, he said he still had vivid memories of what happened there.
The largest and most infamous extermination camp, between 1940 and 27 January 1945 the Nazis killed more than a million people at Auschwitz, near Krakow.
The vast majority were Jews but also Poles, Roma (Gypsies) and Russian prisoners of war perished there.
Trains filled with victims from throughout occupied Europe arrived at the camp almost every day between 1942 and the summer of 1944.
Mr Evans, now 86, and nearly deaf, due he said to wartime bombing and shelling, was ordered to work as a coal miner and held in a sub-camp next to the main facility in 1944.
He said he was at Auschwitz for about a year after being transferred from a PoW camp at Lamsdorf.
Part of a rearguard party of British soldiers protecting the retreating troops on Dunkirk beach in 1940, Mr Evans was captured while receiving treatment in hospital after taking German machine gun fire in a shoulder.
His suffering did not end there. Four years on, he told how he was beaten to "within an inch" of his life by Nazi SS guards at Auschwitz when he refused to work.
But he broke down when he described the sort of treatment the SS dished out to the Jews and other inmates. He said his own troubles paled into insignificance.
"We arrived at Auschwitz in the very same cattle trucks that carried the Jews and others to their deaths," said Mr Evans, a soldier with the 1st Battalion of the Royal Welch Fusiliers.
"We were separated from the Jews by barbed wire fencing and we'd stand and watch when trains brought in cattle truck after cattle truck of people.
Mr Evans served with the 1st Battalion the Royal Welch Fusiliers
"The SS guards would be shouting before the train had even stopped at the men, women and children inside.
"I remember the women and children. I remember little kids who were totally bewildered, who didn't understand what was happening or why they were there.
"We'd watch them all going to the gas chambers and then horse-drawn wagons coming out with dead bodies.
"The bodies would then be burned - the smell was awful. We just couldn't believe people could do such a thing."
He sobbed: "I saw Jews being beaten and shot and sometimes I'd wish they'd shoot me, especially after I was beaten to within an inch of my life.
"I walked up the tracks leading to the camp many times and I'd wish that the train would come off the tracks and crash through the fences and the huts and destroy the camp."
Mr Evans remembers walking along the railway tracks at Auschwitz
Mr Evans, a widower, added that he would never be able to forgive the Germans for what they inflicted on him, the Jews, and his fellow soldiers.
"We saw Himmler (leader of the SS) at Auschwitz quite often," he said.
"We were told by his SS guards not to speak or associate with the Jews, but we would and barter with them for things like food and cigarettes.
"We were fed on one slice of brown bread a day with water used to cook spuds, but the Jews were probably on worse than that."
Mr Evans said his memories of Auschwitz were still difficult to live with.
"When I watch programmes about the extermination camps on TV I cannot sleep," he added.
"I end up getting out of bed in the middle of the night and sitting in the kitchen for hours.
"I don't have any children of my own, although I have a nephew, and most of my friends have died, so I'm alone with my memories."
Mr Evans and his comrades fled Auschwitz shortly before the Russians liberated the camp.
"The SS got us out because they didn't want to hand us over to the Russians," he said.
"We could either march towards the Russians or towards our troops and we decided to head towards the British.
"We marched six or seven weeks through Poland and into Germany. I was wearing wooden clogs and slept rough until we found our troops in Bavaria."