David Cameron is in Poland to visit Nazi death camp Auschwitz.
The Prime Minister is travelling to the notorious site on the way back from Turkey, where he held talks with President Recep Tayyip Erdogan.
The trip to Auschwitz, the first by Mr Cameron, was heralded in his speech to the Israeli Knesset in March.
He has expressed his determination that memories of the atrocities are kept “strong and vibrant”.
“I want every child in Britain to learn about the Holocaust and to understand just how vital it is to fight discrimination and prejudice in our world,” he said.
“It is vital that we do all we can with our international partners to preserve the site at Auschwitz.”
Karen Pollock, chief executive of the Holocaust Educational Trust, said Auschwitz was the site of the “most heinous crime in our shared history”.
“He will see train tracks that brought Jews from across Europe in droves, the crude stables in which they were kept and the gas chambers in which they were ruthlessly murdered,” she said.
“Over the last 15 years, with the support of Government funds, we have taken 25,000 students and teachers to visit Auschwitz-Birkenau. They come back describing it as life-changing. When the Prime Minister follows in their footsteps he too will benefit from that unique experience.”