The Auschwitz survivor changed things for Leon Bass. She had come to speak to some of the classes at Benjamin Franklin High School in Philadelphia. It was a predominantly black school and in 1968 it was "under a state of siege," according to Bass, who was principal then, as he is now. The tide of militance had risen to the point where there was a strong effort among the students to change the school's name to Malcolm X High School. Bass came to listen to the woman, to hear what she had to say.

"She was talking about what happened," Bass says quietly. "The students were laughing. They didn't trust anybody white and they didn't believe her. I stood up and said, 'What she's telling you is true. I was there.' "

Bass remembered how he had felt staring at the horrors of Buchenwald. "At 19, I came into the feeling that I was put upon for being black, and I was," he says now. "But standing there, I realized that suffering was universal, that here were people who had this happen to them simply for being who they were."

He began to lecture to students at other schools about what he had seen. "I realized that in another 20 years, we the liberators will all be gone," he says. "Who's going to tell them what happened? My history books made slavery sound like a nice happy time, like I would have had a good time working on a plantation. That can't happen this time. That's why I want to make sure these kids know. Because if you don't take stock of this, you can be had, you can be used. You can become a victim, or a perpetrator."

There was a war on. That's how Walter Mietus saw it. The liberators were not there to bring comfort; that would come later. They were there to flush out the enemy and to look into faces that looked into theirs as if they were not sure the Americans were going to be treating them any differently.

"It wasn't like the officers, it wasn't like the generals. We didn't see the total picture," says Mietus. "We didn't understand. In a situation like that you become hardened. You control your emotions. You felt sorry for them, but you felt sorry for yourself. The people in the prisons could sense that some of the soldiers -- you could see it in their eyes --they didn't give a damn." The soldiers had to keep a door shut, he explains, otherwise you couldn't take it, the buddy dying next to you, the constant strafing, the friend who was captured and then found dead, the gun still stuck in his mouth. By the time they entered the camps they were hollow men, emptied of everything but the will to live.

"I hope the people in those camps who remember us, I hope they forgive us," Mietus says now. "Because we had gone through hell, too."

This week, Bass and Mietus will take part in the first international gathering of representatives of the nations that took part in liberating the Nazi concentration camps. The International Liberators Conference will take place here over the next three days -- under the auspices of the U.S. Holocaust Memorial Council, in the shadow of recent attempts to claim the slaughter never happened, in the light of the memories, the photographs, the testimony and the attempts to come to terms with the horror.

Attending the conference will be the generals and the diplomats, the historians and the archivists, the former members of war crimes tribunals, and the experts who have spent lifetimes searching for comprehension and context. And then there will be those, like Bass and Mietus, for whom that time was locked away for years.

The title of liberator seems to hang loosely around them, connoting conquering, compassionate heroes when they were actually just kids who stumbled in and blinked their eyes and stumbled out again -- the foot soldiers, armed with cigarettes and chocolate bars, marching into history's maw.

They got married, got jobs, settled down. In some ways it is hard for them to reconcile the savagery they saw with the modest peace of their lives now, with the way they put it behind them, with the way life went on. "One of the hardest questions I was ever asked," says Bass, "came from a student who said, 'Mr. Bass you knew about this in 1945 and you didn't say anything until 1968. How come?' I did a job on myself on that. I just didn't deal with it. I was too busy trying to make a buck and raising a family. Now I think, 'Leon, you blew it. You had a chance, and you blew it.' "

Now he remembers how green the grass was, how the trees were just beginning to come out and the weather was mild and sunny. Leon Bass and the rest of his all-black company had finally shipped out in October 1944 for Southampton, arriving on the continent in time for the Battle of the Bulge. Now it was April, and he and his buddies were bivouacked in the town of Weimar. From there they went to a place he'd never heard of, a place called Buchenwald.

He remembers how, as they approached in the late morning sunlight, it looked like some beautiful suburban community to a city kid like himself, born and raised in Philadelphia. He remembers walking in and meeting a prisoner who began to show them around. To show them things that still make Leon Bass bury his face in his hands, things that force his eyes to freeze and to stare straight ahead.

"I saw the walking dead," he says. "They had eyes devoid of any kind of light." The prisoners wore striped clothing and wooden clogs; their heads were shaved and their bones seemed ready to break through the skin. They walked on. "I saw a fellow wretching out a window. I looked in windows and saw people too weak to get up from the wooden planks they were lying on. I thought, 'Oh my God, who would do this?' "

They walked on. The young man saw dead bodies stacked up next to the crematorium, the matchstick arms and legs, the open eyes, the open mouths. The stench everywhere was overwhelming. He saw the clothing piled outside the crematorium, the small frayed sweaters, the tiny shoes, children's clothes. He went in and saw the charred remains of rib cages and skulls.

On the way back, no one spoke. "I didn't want to talk," says Bass now. "No one could tell me how people could do this. No one could tell me how people could let them."

Walter Mietus had spent 400 miles slogging through the mud and the misery and the killing that had brought him from the Rhine River to Weimar. He was an infantryman, what they called a dogface then, out there on the front lines of the fighting, taking the towns one by one. When his sergeant ordered him on the truck to go with other members of his company to Buchenwald, Mietus wanted no part of it.

By that time, Mietus knew what it was to be a liberator. He and his buddies had marched into labor camps and prisoner-of-war camps, and they had seen the stricken faces, heard the cracked voices, listened to the pleas they could do nothing about. "They'd ask, 'What kind of things are you doing for us?' " Mietus remembers. "But I was just a foot soldier, I couldn't do anything."

After the war, Walter Mietus also forgot. "After the war I worked hard to forget," he says now, in the living room of his home in Adelphi, Md., a soft-spoken man who looks up shyly from the yearbooks that are part of the memorabilia of those years, books with titles like "We Ripened Fast."

In the beginning, forgetting was easy, even though he was in Germany for eight months after the war ended. There were dreams of going home, of getting jobs, there were friends to counsel as the Dear John letters started trickling. "We were just breathing very deeply and trying to savor life," he says. "We were getting back into the flow." The stories in "Stars and Stripes" had names like Treblinka, Dachau, and Auschwitz in them, but the conversations among his friends did not. "People wanted to talk about the light things, how they swapped a pack of cigarettes for a camera, or a bag of flour for a Volkswagen," Mietus says.

When he came back home to Chicago, the silence grew. "I couldn't talk about it, I couldn't," Mietus says. "I felt that people wouldn't believe me. They would think I was telling them war stories." Still there were moments that would trigger the memories, moments when he would be watching a newsreel or a movie, and the images on the screen would disappear and be replaced by the lingering images in his own mind.

He got a job in a Chicago electrical company and worked his way up. Eventually he went back to school and received a doctorate in industrial education. He teaches now at the University of Maryland and lives with his wife of 20 years in a house where the German swords and the Bronze Star and the swastika signed by all the survivors of Charley Company are put away neatly in the basement. The memories were put away as well, until a letter from Emory University came in 1978, asking him to contribute to something called "Witness to the Holocaust: An Oral History Project."

"I hadn't dealt with it at all," he says. "But I started thinking about it. Everything's changed, everything keeps changing, but which way, we don't know. That's why it's important to understand what happened. And we still don't know. We still don't have the whole picture. It bothers me. It would be a real tragedy if we did not take a lesson from it."

What he saw has changed him, Mietus thinks now. "I think I look at life differently. If I got shot down in a promotion or something, if something goes wrong, it's not going to destroy me. I want to value every moment of life." It made him closer to God as well, although not to the idea of religion. "The Germans wore belt buckles," he says, "that said, 'God is with us.' "