In his youth, growing up in the former Yugoslavia, he dreamt of becoming an artist, a painter. Instead, war came, and he was pressed to join the local Bosnian Serb militia. As a resident of the ethnically mixed Dobrinja district of Sarajevo, his job was to kill his neighbours. The very same people with whom Nebojsa Opacic had gone to school, played football and flirted became his mortal enemies. He held an assault rifle, went on patrols, and bowed to the orders of his commanders as he helped to lay siege to Sarajevo. He was terrified. Daily he risked his life dodging mortars and rockets.

And then one day, the fighting stopped. Opacic, then in his mid-twenties, handed over his guns. Peace negotiators drew an invisible line right through the middle of Dobrinja. And, as quickly as they had begun shooting at each other, he and the Bosniak Muslims of the neighbourhood resumed old friendships, acquaintances and business ties. He regularly drinks beers with former fighters of the opposing side. They crack dark jokes about the mortars and rockets they used to fire at each other.

"The people didn't want to have a war, but when it broke out everyone went to their side," he says, now 51, haggard, and sipping hot tea in a cafe along the demarcation line on a brutally cold January afternoon. "When it stopped, the people started to live together again. As long as you weren't a war criminal, you were alright. We were friends before the war. We were friends after the war."