This year's observance of the International Remembrance Day on Jan 27- the anniversary of the liberation of the Auschwitz concentration camp - falls at a time when there are reminders all around us of the dangers of forgetting. This year marks two decades since the genocide in Rwanda. Conflicts in Syria, South Sudan and the Central African Republic have taken on dangerous communal dimensions. Bigotry still courses through our societies and politics. The world can and must do more to eliminate the poison that led to the camps.

I visited Auschwitz-Birkenau last November. A chill wind was blowing that day; the ground was rocky underfoot. But I had an overcoat and sturdy shoes; my thoughts went to those who had had neither: the Jews and other prisoners who were forced into the camp. I thought of those captives standing naked for hours in icy weather, torn from their families and shorn of their hair as they were readied for the gas chambers. I thought of those who were kept alive only to be worked to death. Above all, I reflected on how unfathomable the Holocaust remains even today. The cruelty was so profound; the scale so large; the Nazi worldview so warped and extreme; the killing so organized and calculated nature.

The barracks at Birkenau seemed to stretch to the horizon in every direction - a vast factory of death. The "Book of Names" identifying millions of Jewish victims filled a room yet contained just a fraction of the toll, which also encompassed Poles, Roma, Sinti and Soviet prisoners of war, dissidents, homosexuals, people with disabilities and others. I was especially moved by a video showing European Jewish life in the 1930s - scenes of family meals and visits to the beach, musical and theatre performances, weddings and other rituals, all savagely extinguished through systematic murder unique in human history.