The last time William Lowenberg arrived in Warsaw, he leapt out of the cattle car and witnessed a ruined city in flames.

“They took us from Birkenau to Warsaw. We thought they were going to kill us. But they marched us into the ghetto, which was burning and we slept on the streets. There were no barracks as of yet,” recalls the San Franciscan.

The Nazis put Lowenberg and his fellow Jews to work burning bodies and prying gold out of the mouths of the dead.

Sixty-five years later, Lowenberg will arrive in the city not in a boxcar but on a military jet. Lowenberg has been named to a presidential delegation attending an April 15 commemoration of the Warsaw ghetto uprising.

The German-born, Holland-raised Lowenberg “hasn’t been in Poland since Auschwitz,” and said he’d taken an oath to never return. In fact, when the call initially came from the White House, Lowenberg refused it.

“Then I thought about it and I talked to my children. They said, ‘Dad, you can’t turn the White House down.’ So, I called back.”

Since agreeing to return to Warsaw, Lowenberg admits he’s been “staying awake a few nights a week,” haunted by his hellish memories.

“But I have to do this. I decided I didn’t want to turn my government down.”