Video courtesy of jn1.tv
Talking to The Associated Press on Thursday, the 83-year-old Gutenbaum recalled people in the basement lying on the floor in utter silence with no clothes on in that "infernal heat," but then collecting the strength to stuff ventilation and cracks in the walls to prevent smoke getting into the basement.
They would come out at night, when the German troops were not in the ghetto, to look for water or to cook a meal on fire made from broken furniture.
Gutenbaum, his mother and little brother hid with some others in the basement for 12 days, surviving the horror of the uprising - an against-all-odds revolt by hundreds of lightly armed Jewish fighters against a much larger Nazi force that broke out 70 years ago on Friday.
He is among the ever-shrinking group of survivors from the ghetto attending a commemoration led by Polish President Bronislaw Komorowski in Warsaw.
The Nazis set up and sealed off the Warsaw Ghetto in 1940, gradually tightening the terror there, cutting off the Jews from medical and food supplies and systematically sending them to death camps from a departing point called Umschlagplatz. Residents were also decimated by hunger and diseases.
Gutenbaum recalled seeing bodies of dozens of children in the streets, "some covered by paper, some not covered, and carts taking the bodies to be buried in the cemetery in Okopowa street."
'Acts of heroism - a testimony to honor'
Europe's first open revolt against the occupying Nazi Germans, the Warsaw ghetto uprising broke out on April 19, 1943 when the Nazis decided to liquidate the ghetto and intensified transports of some 50,000 remaining residents to Majdanek and other death camps.
The fighters "knew that they had to die, but they wanted to leave a trace of their existence, hence those acts of heroism, a testimony to honor," Gutenbaum said.
He recalled how German troops came into the basement, forced everyone out at gunpoint and took them to Umschlagplatz.
"You cannot even begin to describe what was going on at Umschlagplatz," Gutenbaum said. "Those SS men were bullying everybody, beating them, smashing skulls, demanding jewelry, demanding watches."
Gutenbaum's mother and brother were killed in the gas chambers of Majdanek, but he survived with the help of other inmates, was moved to other camps and liberated by the Soviet Red Army.
"The fact that I survived is a matter of luck," the retired robotics engineer said. "Maybe I was at the wrong places, or rather at the right places at the right times."