BERLIN — At a time of rising nationalist and authoritarian movements, Angela Merkel on Friday made her first visit as Germany’s chancellor to Europe’s most potent symbol of extremism, the Auschwitz-Birkenau death camp, and warned that liberal democracy must be protected against “a very dangerous historical revisionism.”

Ms. Merkel, who has come to be seen as one of the world’s leading defenders of tolerant, democratic ideals, stepped into the Nazi camp in southern Poland where more than a million people, most of them Jews, were murdered. On a frosty morning, she and Prime Minister Mateusz Morawiecki walked beneath the wrought-iron gateway with its infamous promise, “Arbeit Macht Frei,” or “Work Sets You Free.”

Her visit marked a decade since the founding of the Auschwitz-Birkenau Foundation to preserve the site as a memorial for future generations. But as anti-Semitism and right-wing extremism strain societies across Europe, and a growing number of Germans question their country’s postwar culture of remembrance and atonement for Nazi crimes, the symbolism of her presence at the site resonated beyond the anniversary.

After touring a laboratory that preserves artifacts like the piles of shoes, suitcases and human hair that she viewed in the camp’s museum, the chancellor addressed Germany’s “enduring responsibility” to acknowledge its history as the perpetrator of the Holocaust and war crimes.