It was an artillery shell in the middle of the night that plunged Sara Pechanec's family head-first into the cruel realities of war. In the spring of 1992, Serbian paramilitary forces began their notoriously brutal siege of Sarajevo as the Balkans descended into an orgy of violence and ethnic cleansing.
Day after day the Serbian guns fired down on to their targets from the hills surrounding the city, pummelling what was once one of the most religiously diverse metropolises in Europe. It was only a matter of time before the Pechanec household took a direct hit.
"A shell landed on our house in the middle of the night and destroyed everything in an instant," Mrs Pechanec, now 52, recalls. "All we had left was each other and hope. For the next six months we spent our entire lives in an underground room just waiting to die."
As the Bosnian Muslim woman huddled in a dark cellar with her husband and 10-year-old daughter, she wondered how she'd ever escape the maelstrom engulfing her city. Little did she know that an astonishingly brave decision by her parents, half a century earlier, to give sanctuary to a family the last time war engulfed the Balkans would eventually lead to her own remarkable rescue.
As video footage of the Sarajevo siege was beamed across the world on nightly news bulletins, a Jewish family in Jerusalem watched the events unfold on their television set.
For the Kavilios, Sarajevo had always held a warm place in their hearts. Their children had grown up on stories of how it was thanks to a kind-hearted Muslim family that Yosef Kavilio, the family patriarch, was able to escape the Nazi occupation of Yugoslavia during the Second World War and bring his family to Jerusalem.
It was Mrs Pechanec's mother and father, Zejneba and Mustafa Hardaga, who had risked their lives to shelter Yosef throughout 1941 and 1942, as Germany's Gestapo and the Croatian Ustasa regime joined forces in liquidating Jews, Serbs, gypsies and political opponents.
The Hardagas became the first Muslims to be recognised as Righteous Among the Nations, the official title that Israel bestows on non-Jews who took extraordinary risks to save Jews during the Holocaust.
Now, as the shells rained down on Sarajevo once more, it was time to return the favour. Mustafa had died long before the tumultuous break-up of Yugoslavia, but an ailing 76-year-old Zejneba and her youngest daughter, Sara, were still living within the shattered remains of Sarajevo.
Throughout December 1992, employees at Yad Vashem – Israel's official Holocaust memorial authority – vigorously lobbied their government to organise a rescue. Using contacts in Sarajevo's small remaining Jewish community, the family were eventually located in their cellar and desperately needed medicine was smuggled to Zejneba. Finally, on 5 February 1993, the family made their way out of the besieged city in a refugee convoy headed for the Croatian border which had been organised by Jewish aid agencies.
"When my parents decided to help the Kavilio family during the Second World War, they never could have imagined that, 50 years later, they would need help from the same family to save them from a similar fate," recalls Mrs Pechanec, who flew from her home in Israel to Britain this week to retell her family's story in a series of lectures to mark Holocaust Memorial Day. "Fifty years later in exactly the same place – it's almost unimaginable."
Through a remarkable twist of fate, both the Kavilios and the Pechanec/Hardaga families now owe their lives to each other.
Even before the Second World War broke out, the two households had been firm friends in what was at the time one of the most racially and religiously mixed areas of the world. A photograph in Yad Vashem's archives shows Tova, one of the Kavilios' daughters, playing at the feet of Zejneba at the Hardagas' house in 1940. (When Zejneba finally escaped to safety in Israel, it was Tova who greeted her on the runway). Mustafa and Yosef were also business partners, owning a pipe factory on the outskirts of the city.
But the following year, spring 1941, German planes bombed Sarajevo, destroying the Kavilios' home and sending the city's Jews fleeing into the hills. Yosef returned to the city to co-ordinate his family's escape and was immediately taken in by the Hardegas, even though they lived opposite the Gestapo's headquarters and would have been shot on the spot if they were found harbouring a Jew.
In the testimony he gave to Yad Vashem, Yosef described the family's remarkable kindness. "The women of the family would hide their faces under a veil in the presence of strangers," he explained. "Never before had a strange man stayed with them. They welcomed us with the words: 'Josef, you are our brother; and your children are like our children. Feel at home and whatever we own is yours.'" The women never wore veils in front of Yosef again.
Eventually the Ustasa regime caught up with Yosef but he was spared being transported to Jasenovac concentration camp because the winter snow had made the roads impassable. Instead he was put to work in a snow-clearing chain gang. He escaped to return to the Hardaga household once more before joining his family in Italian-occupied Mostar. From there they made their way to Palestine and settled in Jerusalem.
Sara Pechanec, who was born after the war in 1957, only found out about her family's bravery after her father's death. But even then she wasn't surprised to find out that her father and mother had taken in a Jew.
"Our home was always very open to all sorts of people," she says in an accent flecked with both Balkan and Hebrew tones. "It was a very democratic place. We were always taught that you can have all the money in the world but without friends you will be very alone. My mother always told me, you might not be able to choose how pretty or rich you are, but you can choose how good you want to be. That was the way she talked."
With such a strong bond between the two families it is perhaps no surprise that when Zejneba and her daughter finally arrived in UN- controlled Croatia, the Israelis, in recognition of the role their family had played in helping the Kavilios five decades before, asked them which country they wanted to relocate to. They both chose Israel.
Mrs Pechanec said: "My mother made it very clear. She said she wanted her biological children to be with their non-biological children and by that she meant the Kavilios."
For Mrs Pechanec, now in Britain giving lectures on her experience, her journey to Israel has also provoked a spiritual journey towards Judaism.
"In my heart I had always felt Jewish," she says. "We lived in the Jewish area of Sarajevo and I had always been fascinated by our neighbours. In my mind we all worshipped the one, same God anyway."
Zejneba Hardaga died within a year of arriving in Israel but just before she passed away her daughter told her she wanted to become a Jew. "That turned out to be one of the happiest days of my life. She just turned to me, smiled and said: "If you want to do something, don't talk about it, do it." It was her way of giving me her blessing."