Urszula was one of four children born to Franciszek and Jadwiga Kaczmarek, who lived in the industrial city of Poznan in western Poland. The family lived at 11 Smolnej Street. Like their parents, the Kaczmarek children were baptized in the Roman Catholic faith.
1933-39: As one of the older children in the family, Urszula helped her mother with the housework. She was 10 years old when the Germans invaded Poland on Friday, September 1, 1939. German planes bombed Poznan that same day, and German troops entered the city nine days later. Poznan was in an area of Poland that became formally annexed to Germany [a result of the German-Soviet Pact]. The city was renamed Posen at the end of the month.
1940-43: After the city was occupied, Urszula's parents were among the many citizens put to work as conscript labor for the Nazis. Urszula was left to take care of her younger brother and sister. One day in late 1942, while playing by the house, they were rounded up during a random "street sweep" by the Nazis. That winter, Urszula was deported to a forced-labor camp for children located within Lodz's Jewish ghetto. When she became ill, the guards dragged her into the snow, poured cold water on her, and left her outside.
On May 9, 1943, Urszula died of pneumonia. She was 13 years old. The camp records listed her cause of death as a heart attack.