The Duke of Cambridge has laid a wreath where ashes of victims of the Holocaust are buried at a memorial in Jerusalem.
Prince William visited Yad Vashem, the World Holocaust Remembrance Centre, after arriving in Israel on the first official trip there by a UK royal.
He was given a short tour of the museum before meeting two survivors of the Holocaust, in which six million Jews were murdered during World War II.
The duke’s trip covers Israel, Jordan and the Palestinian territories.
He was joined by UK’s Orthodox Chief Rabbi Ephraim Mirvis during his visit to Yad Vashem.
After seeing a display of shoes left behind by Jews killed in a Nazi extermination camp, Prince William told reporters: “Terrifying. [I’m] trying to comprehend the scale.”
As well as being a major documentation and research centre, Yad Vashem puts emphasis on explaining the Holocaust through individuals’ stories, their possessions and artefacts.
Later, the duke was greeted by Israel’s Prime Minister Benjamin Netanyahu and his wife, Sara, at his residence.
Neither the duke nor Mr Netanyahu made any comment to waiting reporters.
The duke will also meet the country’s President Reuven Rivlin.
His day will round off with a visit to the city of Jaffa, where he will meet young Arab and Jewish Israelis playing football together, and will join them in a penalty shoot-out.
The young people are involved in two charities – the Equaliser and the Peres Centre for Peace – which focus on bringing together youngsters of different religious and ethnic communities through football.
The duke’s five-day trip is the first official royal visit to Israel and Palestinian territories.
Kensington Palace has stressed that it is non political, as with all royal visits.
But the BBC’s Yolande Knell, who is in Jerusalem, said it would be extremely difficult for the prince to keep it that way, despite the careful choreography of the trip.
She said Israeli and Palestinian officials had pointed out to her it was a highly politicised place so people would be scrutinising his every step and every comment.
On Wednesday, the duke will visit Ramallah in the occupied West Bank and will meet the Palestinian president.