WARSAW, Poland (AP) _ The fat Nazi officer reveled in jumping on prisoners' backs at daily roll call. Leon Stasiak can still hear the dry sound of ribs cracking.

He winces at the memory of the Nazi concentration and death camp called Auschwitz.

``Dangers like Auschwitz are still threatening,'' the 79-year-old Stasiak says, his voice rising. He was a prisoner for 2 1/2 years at the camp, which was liberated by Soviet soldiers on Jan. 27, 1945.

``There is no crime or cruelty which people would not be capable of doing to people,'' said Arnold Mostowicz, 80. A Jew like Stasiak, he spent four months at Auschwitz in 1944.

For Jan Zdebik, a Pole whose fluency in German helped him survive four years at Auschwitz, the camp is a symbol of atrocities still committed, of the excesses of war from Rwanda to Chechnya.

The Nazis built Auschwitz in 1940, initially for Poles who actively opposed Hitler's occupation.

The Birkenau subcamp went up two years later, intended to carry out the extermination of Europe's Jews, who accounted for 90 percent of the camp's 1.5 million victims.

At Auschwitz, death came in the gas chamber, from phenol injections, beatings, hangings, shootings. It followed slow starvation, typhus, hours at roll call in bone-chilling cold.

In addition to the Jews, Auschwitz exterminated 75,000 Polish gentiles and 20,000 Gypsies. It killed 15,000 Soviet prisoners of war, German homosexuals and mentally ill. In all, it took citizens of some 28 nations.

A Communist activist before the war, Stasiak arrived at Auschwitz in October 1942 and was spared immediate death because an SS officer was impressed that his batch of prisoners had survived Buchenwald. Slaves in good condition were prized and strong young men were bounced from work camp to work camp.

Each day was a nightmare at Auschwitz:

Up at 5 a.m. At the lavatory you could easily fall through the thin planks and drown. And you had only until the guards counted 20, then you were beaten away.

Food was scant and what there was gave diarrhea. There was never enough water for washing and guards made a sport of beating the unwashed.

Prisoners were so tightly packed in barracks at night that all had to turn over at a given sign.

When someone escaped, 10 others were chosen to die by slow hunger.

``It was barbarism,'' said Menachem Joskovich, 70, a rabbi and Birkenau survivor. ``They laughed when they shot at women with children in their arms.''

Many survivors have found it difficult to go back _ or to reconcile with the Germans.

Mieczyslaw Zawadzki, a Pole who is now 75, spent four years at Auschwitz. He returned for the first time in 1955, taking his brother.

``I got so anxious, so emotional that until the end of the day I could not drive my car; he had to do it,'' Zawadzki recalled. ``And for many days I couldn't collect myself.''

Only now can he almost control his emotions when he remembers.

Stasiak has been to Auschwitz only once since the war.

In 1947, he visited for the hanging of camp commandant Rudolf Hoess in the vain hope it would free him from constant nightmares of suffocating under heaps of dead bodies.

Germany offered compensation to victims after the war. Stasiak, who lost his parents, two brothers and four sisters, gave all his to charity.

``The Germans murdered my whole family,'' he said. ``I don't want them to have settled accounts with me.''