On January 27, 1945, troops of Russia's Red Army liberated the concentration camp of Auschwitz in Poland in the closing months of the Second World War.
What they found there has left a scar on humanity ever since.
More than one million people had been systematically gassed and burned – among the nine million slaughtered by the Nazis in death camps, mainly in Eastern Europe.
Six million Jews died, and three million others who included gypsies, communists, disabled people, homosexuals and trades unionists.
January 27 has now been recognised as International Holocaust Day and in Leeds, across Yorkshire, all over Britain and around the world events will be taking place on or near that day to commemorate not only the most horrific genocide in human history, but also other, more recent genocides including those in Cambodia, Bosnia, Rwanda and Darfur.
On Sunday, at 2pm, the Lord Mayor of Leeds, Coun Jim McKenna will light a candle at Leeds Town Hall marking International Holocaust Day.
It will mark the start of an afternoon of commemorations which will include visual art by local schoolchildren, live music from pupils of the David Young Academy, a new piece of theatre by young people from
The Carriageworks Theatre Academy and theatre company Blah Blah Blah, inspired by the life story of Holocaust survivor Eugene Black, and speeches by Makor Youth Group who have recently visited concentration camps across Poland.
The keynote speaker is Mike Love, of Together for Peace, and the event will conclude with a traditional Hebrew memorial prayer sung by Rudi Leavor.
Coun McKenna said: "It is a chance for people to join together in remembrance and I look forward to welcoming as many people as possible to the event. As well as remembrance, the day is about looking forward and trying to create a better, safer future for us all.
"The untold stories of victims and survivors can help us to think about ways we can work together as communities to respect and celebrate differences between us."