The Prince of Wales has said the world is in danger of "forgetting the lessons of the past".
He recalled the "indescribable persecution" suffered by Holocaust survivor Ben Helfgott, who faced the horrors of the Buchenwald concentration camp but went on to captain Britain's weightlifting team at the 1956 and 1960 Olympic Games.
Charles was speaking at a central London fundraiser for the World Jewish Relief (WJR) charity, which is working with people who are fleeing Syria and seeking new lives in Greece, Turkey and the UK.
He told the 500 invited guests: "The work of World Jewish Relief enables us to rally together, to do what we can to support people practically, emotionally and spiritually - particularly at a time when the horrific lessons of the last war seem in increasing danger of being forgotten."
The charity was founded in 1933 to support people fleeing persecution from Nazi Europe.
It created the Kindertransport, which brought thousands of Jewish refugee children to Britain from Nazi Germany between 1938 and 1940.
It now supports vulnerable people in 18 countries through activities including disaster relief, employment skills and providing older people with food, medicine and companionship.
Charles spoke of how he is proud to be a WJR patron because the charity sets an example of "true compassion and true friendship".
It does this by reaching beyond its community to help those in need, regardless of their faith, he said.
Charles has been a long-standing supporter of Jewish communities in the UK and abroad. He and the Duchess of Cornwall have previously attended the commemorative ceremony for Holocaust Memorial Day.
The audience applauded as Chief Rabbi Ephraim Mirvis criticised US President Donald Trump for his "totally unacceptable" and discriminatory travel ban.
The Chief Rabbi talked about how the organisation gives people hope around the world.
But he said: "Not much hope from the United States of America, of all countries, where President Trump appears to have signed an executive order which seems to discriminate against individuals based totally on their religion or their nationality.
"We as Jews perhaps more than any others know exactly what it is like to be the victims of such discrimination and it is totally unacceptable."
Mr Trump's temporary ban on nationals from seven mainly Muslim countries has caused chaos and outrage across the US, with travellers detained at airports and protesters registering opposition to the sweeping measure.
Nationals from Iraq, Iran, Libya, Somalia, Sudan, Syria and Yemen are covered by the order.