By Siafa Lewis

PHILADELPHIA (CBS) — Holocaust Remembrance Day is being marked around the world 77 years after Soviet forces liberated Auschwitz, the largest Nazi death camp. Eyewitness News spoke with a Philadelphia man whose grandfather survived Auschwitz and why it’s so important to share his grandfather’s story.

When Germany invaded Poland in 1939, 15-year old David Wisnia came home one day to find his father, mother and baby brother had all been killed by the Nazis. His older brother ran away and tried to escape, but he too was killed.

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“He was finally found out without papers and taken by cattle car to the concentration camp known as Auschwitz,” Avi Wisnia said.

David, who died last summer at the age of 94, was a Holocaust survivor. In 1942, he was forced to board a cattle car and arrived at Auschwitz on Dec. 14.

David was tattooed and assigned to barracks 15. He was in Auschwitz for close to three years.

Avi, one of his grandchildren, invited Eyewitness News into his home to share his grandfather’s story.

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“Because he was a singer he was invited one night to perform, to entertain for the Nazi guards that were watching over the prisoners of Auschwitz,” Avi said.

Music quite literally helped to save David’s life. But freedom nearly three years later was the result of an escape during a transport from the second concentration camp David was in, Dachau, on the way to a third.

He ran away into the woods and eventually stumbled upon American soldiers.

Avi said there were things his grandfather shared about his time in captivity and others he didn’t, but more important than hearing every last detail is making sure that the horrors perpetrated by the Nazis are never forgotten.

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“An example of what human beings are capable of. Human beings are capable of inflicting great pain and horror on each other. And yet, human beings are also capable of incredible compassion and kindness,” Avi said.