Thousands of people have marched through Auschwitz, the former Nazi-German concentration and death camp in Poland, more than 80 years after its liberation.
Organisers said they were joined by 80 survivors of the Holocaust.
The March of the Living followed a 3km route to the crematoria of Auschwitz-Birkenau as participants paid tribute to the millions of Jews who died and called for an end to antisemitism and intolerance.
"In days when anti-Semitism is raising its ugly head, when there is hatred towards Israel, and when cries rise for the destruction of Israel, we must stand strong and remind and promise the world: never again," Israeli President Isaac Herzog told a news conference before the event.
The participants, many draped in Israeli flags, passed through the notorious "Arbeit macht frei" (work sets you free) gate at the entrance to the camp as the march began.
Anti-Semitic incidents have increased along with protests against Israel in parts of Europe, North America and Australia since Israel launched its war against Hamas in the Palestinian enclave of Gaza.
"We both expressed our hope that the war taking place in the Gaza Strip, which was started by Hamas' attack on Israel, will be able to end, that the hostages who are still in Hamas hands will be able to return home," Polish President Andrzej Duda, standing alongside Mr Herzog, said.
Watch: One survivor reflects on the Holocaust
Survivors who attended the march warned world leaders not to forget the lessons of the past.
Dr Martin Stern said that focusing solely on the Holocaust would mean "fighting the last war," adding "we have a war now. We have to deal with the situation that exists today".
The 87-year-old, who was arrested when he was five years old and sent to Terezin concentration camp in what is now the Czech Republic, said humanity claims to have learned its lesson, but it has "often drawn the wrong conclusion".
Another survivor, Sol Nayman, 89, said the worst part about the Holocaust was that people might forget about it.
Born in Poland, he escaped with his family during World War II to the woods where they fled to the Soviet Union.
Mr Nayman said that, unfortunately, there were still billions of people who claimed to be Holocaust deniers.
"I say to them, come and walk with me through Auschwitz, come and walk me through Treblinka or Majdanek or any camp of your choice. That's where the proof is.
"We will continue to speak about it. We will continue to teach about it, and hopefully it will make a difference one person at a time, one child at a time."
More than 1.1 million people, mostly Jews, died in gas chambers or from starvation, cold and disease at Auschwitz, which Nazi Germany set up in occupied Poland during World War II.
Over three million of Poland's 3.2 million Jews were murdered by the Nazis, accounting for about half of the Jews in Europe killed during the Holocaust.
Between 1941 and 1945 Nazi Germany and its collaborators systematically killed six million Jews across German-occupied Europe, along with gypsies, sexual minorities, people with disabilities and others singled out by genocidal ideology.
Sirens sound as Israel commemorates Holocaust
Israel came to a standstill as sirens echoed across the country on its Holocaust Remembrance Day.
Israelis observed two minutes of silence, with traffic stopping, pedestrians standing still, and daily life pausing in symbolic honour of all of those who perished.
The commemoration, held each year in April or May in accordance with the Hebrew calendar, is separate from International Holocaust Remembrance Day which is marked on 27 January.
Memorial events have also been taking place in schools, government institutions, military bases and in the parliament building.
An Israeli government body supporting Holocaust survivors said that 120,507 of them were living in Israel, down nearly 10% on last year's figure.
