For the past week I have been in Rwanda.

This weekend, the small African nation and the world will commemorate the twentieth anniversary of the start of the 1994 genocide during which more than 800,000 Rwandans, mostly ethnic Tutsis, were massacred in less than 100 days.

Many of us are familiar with the horrors of that time through powerful films and books such as Hotel Rwanda and Shake Hands with the Devil.

But, emotionally raw at these renderings of the genocide are, nothing compares to listening first-hand to survivors' stories and visiting some of the places where this orgy of bloodshed took place.

That said, at the end of a week doing just that, I still find it genuinely difficult to comprehend the barbarism and scale of what happened during those months of 1994 in Rwanda.

How is it possible in the modern world for almost one million people in just 100 days to be hacked or bludgeoned to death mostly by machetes, clubs studded with nails, kitchen knives and iron bars?

How too can it be that husband and wife, neighbour and friend turn on each other because of the perversities of politicians who saw their ethnic rivals as nothing more than "cockroaches".

Discomfiting as such questions are, they are matched only by the pressing issue of how an international community can prevaricate over intervention, ultimately turning its back as the corpses pile up.

When asked this last question some simply reply that it's because it happened in Africa, and what else can we expect?

I have always found repugnant the racist myth that such things are only confined to "primitive" and "darkest Africa". The Nazi Holocaust of the Jews and others happened in Europe. Last month I visited the Bosnian town of Srebrenica, where 8000 men and boys, barely a year after the Rwandan genocide, were massacred in the worst atrocity in Europe since the Second World War.

As I left Rwanda I found myself wondering what we have learned from its atrocities of 1994. As Kofi Annan, then Secretary-General of the United Nations, lamented on the 10th anniversary of the Rwandan genocide: "Such crimes cannot be reversed. Such failures cannot be repaired. The dead cannot be brought back to life. So what can we do?"

The place to start, as I did find out in Rwanda, is not to hide away from those crimes and failures of the past. Rwanda is openly facing up to what occurred 20 years ago. If there is a problem with the way it does this, it's perhaps that this process of reconciliation is sometimes overly imposed through government directives rather than allowing the voices of the people to naturally express their feelings about the genocide.

To be fair to the Rwandan government, though, their task has been monumental in bringing the country back from the abyss. It's all too easy for those of us in the comparatively comfortable West to tell others how to do it better, not least when we previously failed such people when it mattered. If nothing else, 20 years on the Rwandan genocide stands as a stark reminder of the dangers of indifference and the consequences of inaction when people are in need.