Marian Turski, a 94-year-old survivor of Auschwitz, was marking the 76th anniversary of its liberation by Soviet troops virtually, aware that he might never return as the coronavirus pandemic drags on.
Survivors and museum officials said they fear the pandemic could end the era where Auschwitz's former prisoners can tell their own stories to visitors on site.
Most Auschwitz survivors are in their 80s and 90s.
"Even if there was no pandemic, there would be fewer survivors at every anniversary," Mr Turski told Reuters in a Zoom interview from his Warsaw home.
"People at my age who are already vulnerable to many other illnesses are also in the first line of fire for this virus."
The Auschwitz-Birkenau Museum and Memorial preserves the Auschwitz death camp set up on Polish soil by Nazi Germany during World War II.
More than 1.1 million people, most of them Jews, perished in gas chambers at the camp or from starvation, cold and disease.
Today's ceremony marking the camp's liberation will take place virtually, with speeches by survivors, Poland's President Andrzej Duda and Israeli and Russian diplomats, as well as a debate on the Holocaust's influence on children.
Other virtual ceremonies will also take place to mark Holocaust Remembrance Day.
The Memorial has been closed to visitors for 161 days due to the pandemic. In 2019 it was visited by around 2.3 million people. In 2020 that number dropped to around 502,000.
The Museum's director, Piotr Cywinski, acknowledged virtual events and education programmes were not as effective in passing on the lessons of the Holocaust and World War II.
"Nothing will replace witnessing the place in its authentic state, because this isn't just about seeing and listening. This is about looking around, in your own steps, touching, experiencing different perspectives, understanding," he said.
Survivors emphasised the importance of finding ways to keep Auschwitz relevant after they can no longer tell their own stories, amid a rise in far-right movements and anti-Semitism.
In Germany, former finance minister and now president of the lower house of parliament, Wolfgang Schaeuble, warned that "our culture of remembrance does not protect us from a brazen reinterpretation and even a denial of history".
He added that racism and anti-Semitism were spreading through internet forums and conspiracy theories, stressing society's collective responsibility to honour the memory of the Holocaust.
Pope Francis urged people to keep a close watch on ideological extremism, because "these things can happen again".
He spoke three weeks after displays of anti-Semitism surfaced at the US Capitol riot on 6 January and two weeks after one of Montreal's largest synagogues was vandalised and almost set on fire.
Speaking at his general audience, held inside the papal library because of coronavirus restrictions, Pope Francis said it was imperative that the world did not forget.
"To remember ... means being careful because these things can happen again, starting with ideological proposals that claim to want to save a people but end up destroying a people and humanity," he said.
Some Auschwitz survivors, like Bogdan Bartnikowski, 89, said they were optimistic that the pandemic would not end their chances of returning to the memorial and telling their stories.
"I have hope that for sure there will continue to be groups of visitors to the museum," he said.
"Us former prisoners will not be lacking."