Seventy-five years ago today, allied forces liberated the Nazi death camp at Auschwitz. The inhumanity of what they found changed the world forever. Auschwitz became a symbol of the horrors of genocide, anti-Semitism and the Third Reich.
In just five years, more than a million people - the vast majority of them Jews -- were murdered within its walls.
Today, the camp still stands as a memorial, museum and education centre. But for those who lived through it, it will always be a cemetery - and a warning.
"We forget at our peril"
Mayor of London Sadiq Khan is one of many world leaders attending a commemoration ceremony at Auschwitz. He spoke to Euronews' Political Editor Darren McCaffrey.
"The bad news is that 75 years after the liberation of Auschwitz, we're seeing a rise in anti-Semitism across Europe, including London; we're seeing a rise of nativist populism and I think it's really important that we redouble our efforts to remember the real lessons for the Holocaust...We forget it at our peril."
"It's really important that we are vigilant to the rise of hatred, to the rise of anti-Semitism - it is the canary in the coal mine. We've got to make sure, those of us who aren't Jewish, stand shoulder-to-shoulder with the Jewish community and are vigilant toward all forms of hatred."
To listen to the full interview with Mayor of London Sadiq Khan, click on the media player above.