OSWIECIM, Poland — Survivors of the Auschwitz-Birkenau death camp prayed and wept as they marked the 75th anniversary of its liberation, returning Monday to the place where they lost entire families and warning about the ominous growth of anti-Semitism and hatred in the world.

“We have with us the last living survivors, the last among those who saw the Holocaust with their own eyes,” Polish President Andrzej Duda told those at the commemoration, which included the German president as well as Jewish, Christian and Muslim leaders. “The magnitude of the crime perpetrated in this place is terrifying, but we must not look away from it and we must never forget it,” Duda said.

About 200 camp survivors attended, many of them elderly Jews and non-Jews who traveled from Israel, the United States, Australia, Peru, Russia, Slovenia and elsewhere. Many lost parents and grandparents in Auschwitz or other Nazi death camps during World War II, but were joined by children, grandchildren and even great-grandchildren.

They gathered under an enormous, heated tent straddling the train tracks that had transported people to Birkenau, the part of the vast complex where most of the murdered Jews were killed in gas chambers and then cremated. Auschwitz was liberated by the Soviet army on Jan. 27, 1945.

Ronald Lauder, the president of the World Jewish Congress, brought the crowd to tears with the story of a survivor who was separated from his family: The man watched his young daughter, in a red coat, walk to her death, turning into a small red dot in the distance before disappearing forever.

After the end of the war, when “the world finally saw pictures of gas chambers, nobody in their right mind wanted to be associated with the Nazis,” he recalled. “But now I see something I never thought I would see in my lifetime, the open and brazen spread of anti-Jewish hatred.”

“Do not be silent! Do not be complacent! Do not let this ever happen again — to any people!” Lauder said.

Marian Turski, a 93-year-old Polish Jewish survivor, said he did not expect to make it to the next commemoration and wanted to transmit a message to his grandchildren’s generation: That the destruction of the Jews began with small steps that were tolerated. What began with banning Jews from sitting on benches in Berlin evolved in incremental steps to ghettos and death camps. And that such horrors could happen anywhere, even in the United States.

“Auschwitz did not descend from the sky,” he said, crediting those words to Austrian President Alexander van der Bellen, among those present. Calling for people to not be indifferent, he said: “Because if you are indifferent, you will not even notice it when upon your own heads, and upon the heads of your descendants, another Auschwitz descends from the sky.”

As a Jewish survivor recited Hebrew prayers for the dead, the crowd bowed their heads or wiped away tears. Clergymen of other faiths also prayed.