How on earth do you introduce a subject like genocide in school? This is a question I’ve returned to time and again over the last few weeks. It’s something that presents a unique challenge for teachers: to show pupils that people are capable of almost unimaginable cruelty.

In May, I travelled to Bosnia with the charity Remembering Srebrenica Scotland. Our delegation went to Sarajevo, a city devastated by the siege of 1992-95. The next day, we drove several hours towards Srebrenica, where, 24 years ago - half a century after the Holocaust - Europe once again was the site of genocide.

The official number of deaths in the Srebrenica genocide is 8,372. Men and boys were singled out for execution by Bosnian Serb troops, and thousands of women and girls were subjected to acts of sexual violence. But to a teenager in the UK who has no direct experience of war, murder or any of humankind’s worst tendencies, a death count is hard to relate to. Numbers may seem like abstractions, easily filed away in a folder or tucked away in the back of minds.

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For me, certainly, numbers weren’t what stuck in my brain in May, even though there were plenty of shocking statistics - it was seemingly smaller details that lingered.

The Potočari Memorial Centre includes thousands of graves, marked by pointed white headstones, and a vast former factory where, in July 1995, United Nations troops from the Netherlands failed to provide thousands of Bosnian Muslims with the protection they sought. There, I felt a deeply uncomfortable sense of déjà vu looking at pictures of racist graffiti which Dutch soldiers had scrawled with a black marker pen, in sneering capital letters.

One message read: “NO TEETH…? A MUSTACHE…? SMEL LIKE SHIT…? BOSNIAN GIRL!”

Instantly, my mind raced back decades to seeing messages scrawled on school and university toilet cubicles, of women and ethnic groups demeaned by cowardly, anonymous slurs. It was uncomfortable to read back then, but it was easier to brush off when the line between such dehumanising language and where it can ultimately take people wasn’t as clear the memorial centre in Bosnia made it.

Here, then, may be a way to help students get their heads around genocide. Show them the “stages of genocide”, and let them see how relatively innocuous the first few steps might seem. The first of these stages, for example, is simply “classification”, which underlines differences between people by ethnicity, race, religion, or nationality. “Dehumanisation”, where minority groups are vilified - such as in the graffiti about the Bosnian girls - is the fourth stage of 10.

A new education pack is being prepared by Remembering Srebrenica Scotland for use in schools. One of the teachers involved, Dollar Academy assistant rector Robin Macpherson - a board member of the charity - says: “Genocide is not a new phenomenon, but the term is: it was only coined by Raphael Lemkin during the Second World War, and criminalised fully by the UN in 1948. Our attempts to teach it as a concept are therefore far from being fully formed.

“We need to be aware that teaching the Holocaust does not mean that we have taught children about genocide. We have just taught one example, and there are many. This is why Srebrenica is so important, as are Rwanda, Armenia, Sudan and many more.”

Macpherson adds: “To get across an idea of such enormity and to expect children to understand its genesis and nature, we need to do much more in the curriculum. It is a theme that recurs in many subject areas and a discussion at whole-school level on how to approach this is valuable.

“It is absolutely essential that children know how serious prejudice is, and how to confront it.”

Gordon Walker, a retired primary teacher who has also worked in the secondary sector, was part of the Remembering Srebrenica Scotland delegation in May.

Walker was shocked by lack of reconciliation in Bosnia, where tensions between ethnic groups remain high and the 1995 genocide is widely denied. The arrogance of some of the perpetrators of genocide has also lingered in his mind: by filming atrocities as they were carried out, some appeared to consider themselves untouchable.

But as a teacher, says Walker, you must guide students away from any notion that such scenes are crazy, inexplicable events which happen in isolation; students must be shown the context behind individuals’ crimes, the international power dynamics and historical forces that underpin them.

“It’s not just something that happened far away to other people,” says Walker, adding that pupils’ relative familiarity with the Second World War provides an obvious way into the Bosnian genocide. Walker also suggests that teachers might explore parallels with the UK’s history of colonialism, the treatment of Native Americans or - to give lessons a contemporary relevance - the plight of Rohingya refugees from Burma.

P5 (when pupils are aged around 9) is the absolute earliest stage at which Walker would consider discussing genocide, although it would be “quite difficult because you don’t want to go into gory detail”. He stresses, however, that there is a difficult balance to strike with any age group, of “staying factual without being emotional”.

As with Anne Frank’s diary, Walker believes turning to children’s testimonies can help pupils’ understanding of horrendous events - a common question teachers are likely to field, he says, is “How did they still manage to have a childhood?”

Delegates in May saw a string of harrowing accounts of the Bosnian War from children’s point of view, on display at the War Childhood Museum in Sarajevo. Exhibits include a chalkboard and abacus damaged by shrapnel, a playground swing from Sarajevo that reminded children of more peaceful times, and a collection of chocolate bar wrappers that the owner said had “allowed me to connect with a normal childhood”.

Another teacher who was part of the delegation is Pamela Day, acting curriculum leader for dance at Edinburgh’s Broughton High, where the City of Edinburgh Dance School is based.

She plans to bring the subject of genocide into the classroom by using dance, explaining: “This could be done in a variety of ways - as a stimulus for choreography, as a discussion alongside the history of dance which explores gender, social and cultural developments.

“In my experience young people are very concerned with issues around intolerance and injustice and get very passionate about expressing their views. Therefore, I plan on teaching about the genocide and my experience in Bosnia and then getting the students to take part in researching and creating a piece of choreography.”

Their pieces will be performed at assemblies, “which will in turn hopefully connect other students on an emotional level”.

Day adds that there is also “a great opportunity for interdisciplinary work with other departments” and that, while this might create extra work, schools have a crucial role in “raising consciousness of hate crime and intolerance”.

Meanwhile, Macpherson has been working with Fiona Malcolm - a teacher at Braes High School, Falkirk - to improve the Remembering Srebrenica Scotland education pack. One new part of the programme could be sending pupil delegations to Bosnia, just as the Holocaust Educational Trust enables pupils to visit Auschwitz. The charity is also recruiting ex-teachers who have the time to visit schools and is looking to send them on an education delegation to Bosnia in 2020.

Certainly, as I and other members of the delegation in May saw, visiting the site of genocide deepens your understanding of it - and makes it far harder to dismiss it as something with little relevance to our own comfortable lives.