BERLIN — The auditorium at the Humboldt University in eastern Berlin was packed recently as several students who had been expelled by the Nazis nearly 70 years ago took the podium for a panel discussion on their experiences.

"I came to Berlin for two reasons," said Rabbi Leo Trepp, who was born in 1913 in Mainz. "I wanted to study in the rabbinical seminary here, and also the university had the best reputation."

Trepp fled in 1938 after a brief internment in the concentration camp in Sachsenhausen, near Berlin. He lives today in San Rafael and teaches every summer at the University of Mainz.

"I left, because I had to go," he said.

Twenty-two of the 2,200 students expelled in 1933 paid a five-day visit to the university as part of a reconciliation program called Classmates of 1933.

The panel discussion was one of the highlights. Although some of the visitors — in their 80s and 90s — are physically frail, their memories are still clear. And if the former students were generally ready to tell their stories, the current students were thirsty for answers.

After a theology student pressed him, Volkmar Zuehlsdorff, 88, told of a book burning he witnessed.

"We came out after dinner; it was about 9 p.m., and we saw how the bonfire had been prepared. There was a huge pile of wood and a big stage with loudspeakers. At about 10 p.m. it started to rain heavily, and they were supposed to make a fire," he said.

"But they had a lot of gasoline. And then the German Girls Union came, looking very pretty. And the Hitler Youth came after them."

Books were delivered in two large furniture trucks, he said.

Zuehlsdorff said he watched and listened as the young Nazis handed books down the line and threw them into the towering bonfire, saying, "I hereby deliver to the flames the collected works of Karl Marx" or "I am throwing into the flames the works of Sigmund Freud."

The site of the burning, across the street from the main university building, is now marked with a memorial.

"It was so indescribably idiotic. Some of us secretly laughed. Then Goebbels came and gave a speech about the 'insidious Jewish character,'" Zuehlsdorff said. "It was a horrible experience. It is hard to grasp."

Zuehlsdorff left Germany shortly thereafter.