It is Holocaust Memorial Day - 71 years since the liberation of Auschwitz concentration camp, and one of the most sombre dates in the calendar, which not only deserves, but demands, the widest possible observance.
This year, there will be more than 3,500 events across the country, at which the dwindling number of survivors of Nazi persecution will be the most honoured guests.
Those who can still bear witness must be treasured and listened to, for the time is approaching when there will be no living testimony.
And no less attention should be paid to this year’s theme, which is “Don’t stand by”, a warning that indifference and passive acquiescence allow extremism to take root.
The message will not be lost any of the 28,000 pupils from schools across Britain who have made the pilgrimage to Poland since 1999 thanks to the Holocaust Educational Trust.
This is one of the greatest educational programmes of our time. For each of the young people who has passed through the gates bearing the cruelly cynical motto “Work sets you free”, this most heinous of crimes has come alive and moved them profoundly.
They have stood before the exhibits – the hair shorn from women’s heads, the thousands of pairs of spectacles, the suitcases carried by those bound for murder – and the touch of the past has made them shudder.
Back home, their experiences are shared with classmates in carefully-structured sessions, so that awareness of the Holocaust and its lessons for the present and future are learned.
Those lessons are more than necessary ever. The mass of lunatic or malicious Holocaust denial material on the internet grows ever greater, and worse, so does the demented outpouring of admiration for the most notorious act of genocide in history.
There are many among the remaining survivors who have felt impelled to break their silence of decades and dredge up the most searing of memories to counter this, fearing that unless their stories are told, the deniers will ultimately rewrite history.
Their fears have only been deepened by a resurgence of the far-right in Europe. In France, it is achieving a degree of electoral respectability, but its darker side has seen instances of Jewish people leaving communities where they no longer feel safe, let alone welcome.
In Germany, a neo-Nazi minority has been responsible for attacks on immigrants, and the huge numbers of refugees from Syria are in peril of becoming the next targets.
Even in Oswiecim, the Polish town forever scarred by its Nazification into Auschwitz, the pre-war civilian cemetery is shut away behind high walls and locked gates because Jewish graves have been periodically vandalised.
The message of Holocaust Memorial Day, though, goes much wider than Europe.
It is a sobering reminder that vicious hatred flourishes wherever it is allowed to, and when it gains control with the acquiescence of populations who either actively support it or stand by and shrug their shoulders, humanity sinks into a cesspit of evil.
The most depraved of Hitler’s minions would have nodded in approval at the savagery meted out by the so-called Islamic State, the worst excesses of a resurgent Taliban in Afghanistan or the genocide in Darfur.
The Nazi hierarchy would also have applauded how extremism in all these places gained its foothold and then consolidated power – promise a Utopia, kill outsiders or dissenters, and then once support is widespread exercise ruthless control.
Mass graves are still being dug for the bodies of the innocent, atrocities committed in the name of fanaticism, and the deluded fantasy of regimes that will last for a millennium proclaimed.
We should pause and reflect tomorrow, remembering the victims of the Holocaust, but also listen to the echoes they sound for the present.
For the hatred that the Holocaust represents does not only belong to the past. It is part of our age, and the warning from history is for us to have the courage to oppose it.