We're lucky in the UK. From traveling around Europe and the world, I've always felt the UK is one of the most cohesive countries on the planet. We lead our lives, for the most part, sheltered from the most extreme forms of intolerance.
Safe in our homes we see horrific acts of genocide and ethnic cleansing play out in the newspapers and on TV, and of course we feel shock, sadness and anger, but we don't consider for a second that anything like that could ever happen here.
That's how I felt when I saw reports of the massacre of more than 8,000 men and boys in Srebrenica 22 years ago.
As the events unfolded, I was aware of what was going on, of course, but I didn't make it my business to find out any more about it. And I certainly didn't think that anything similar could happen to us here in the UK.
Something like that could only happen in 'other' places, surely.
But when I went to visit Srebrenica in Bosnia Herzegovina last month I discovered that was exactly what they had thought there too.
Bosniaks, Croats and Serbs had lived together harmoniously for hundreds of years - they never thought it could happen to them either.
But it did.
Muslims, Catholics and Orthodox Christians who'd happily lived side-by-side as friends and neighbours were suddenly at war. A creeping, sense of nationalism brought about by the collapse of Yugoslavia had exploded and the results were catastrophic.
Muslim Bosniaks were systematically targeted in ethnic cleansing across eastern Bosnia and pushed into the UN-designated safe zone at Srebrenica.
But the Dutch UN peacekeepers stood by whilst the Bosnian Serb army overran the town in July 1995.
Mirroring the Second World War's Jewish Holocaust, civilian refugees who had sought safety in the nearby UN camp at Potocari after Srebrenica fell were rounded up and screened by soldiers. Women and girls were separated from the 8,373 men and boys who were sent to their deaths in mass executions.
I had the privilege of meeting a man who miraculously survived one of these mass killings. He was 17 when he was lined up with scores of other Bosniak men and boys and shot.
He and another man managed to survive by playing dead among the bodies and then trekking across country to safety, while severely injured, malnourished and dehydrated.
Lessons from Srebrenica
Now he takes part in the sponsored Lessons From Srebrenica educational programme that I was invited along to, reminding people of what happened in Bosnia 22 years ago and inspiring people to take action in their communities that will help to create a better, safer and stronger society.
The programme, run by DCLG-supported charity Remembering Srebrenica, aims to motivate people of all ages to strengthen their communities by challenging hatred and intolerance by remembering the worst crime in Europe since the Second World War.
When the Second World War ended we said 'never again' would we allow the systematic persecution of a people.
But we've said 'never again' too many times and have stood by and watched atrocities like the Srebrenica genocide play out.
Wikipedia lists 33 genocides since 1945. That's almost one for every two years since the end of the war, and sadly too many to list here.
Even now Daesh is hell-bent on wiping out Shias, Yazidis and Christians in Syria and Iraq and Rohingya refugees are fleeing military persecution in Myanmar to neighbouring Bangladesh.
And we'd be naïve to believe that something similar would be impossible here. We need to remember that the genocide at Srebrenica happened in Europe at the end of the 20th century.
The events of the 1992-1995 Bosnian War left society deeply divided. Even now they're still feeling the effects of the hatred stirred up more than two decades ago.
New wave of nationalism
At home, across Europe and in America we're seeing a new wave of nationalism and a resurgence of the racial and religious intolerance we swore we'd never allow to surface again.
The UK is increasingly divided and, as an Asian Muslim man, I'm noticing it more and more.
I've encountered racism and Islamophobia throughout my life - my physical appearance and my name may both lead people to make judgements about me and my community. But as chief executive of Barnardo's, the UK's largest and oldest children's charity, I'm in a privileged position.
Many BAME young people do not enjoy that privilege.
UK society is becoming more unequal and people feel empowered by the divisive rhetoric they hear in the news or read in the papers.
Srebrenica is a dark stain on humanity that happened on our doorstep in our living memory within a seemingly well-integrated society.
Consequences of hate
It's our duty as a liberal, tolerant society to open our eyes and the eyes of others to the consequences of hate and discrimination to make sure nothing like it can happen again.
We need to set examples to children and young people to embrace our differences and treat everyone with the love and respect they deserve; we need to empower them to speak up for themselves and other people.
As a mathematician, chaos theory springs to mind here - if enough butterflies beat their wings at the same time, we can cause a hurricane.
That's how change happens. But it starts with just one person; one voice calling out prejudice or intolerance where they see it.