At the start of the Second World War, Kolbe was residing in the friary at Niepokalanow, the “City of the Immaculata.” By that time, it had expanded from 18 Friars to 650 Friars, making it the largest Catholic house in Europe.
When Poland was overrun by the Nazi forces in 1939, he was arrested under general suspicion on 13 September but was released after three months.
On being released, many Polish refugees and Jews sought sanctuary in Kolbe’s monastery. Kolbe and the community at Niepokalanów helped to hide, feed and clothe 3,000 Polish refugees, (of which approximately 1,500 were Jews).
Because the guards wanted the cell emptied, the remaining prisoners and Kolbe were executed with a lethal injection. Those present say he calmly accepted death, lifting up his arm. His remains were unceremoniously cremated on 15 August.
Kolbe was sent to the work camp. This involved carrying blocks of heavy stone for the building of the crematorium wall.
In July 1941, three prisoners appeared to have escaped from the camp; as a result, the Deputy Commander of Auschwitz ordered 10 men to be chosen to be starved to death in an underground bunker. When one of the selected men Franciszek Gajowniczek heard he was selected, he cried out “My wife! My children!” At this point, Kolbe volunteered to take his place.