After the German invasion of Poland in 1939 that started WWII, Jews were herded into a ghetto and a wall constructed around it. Disease ran rampant. Irena Sendler falsified documents in order to pose as a nurse so she could get into the ghetto to bring food and supplies.
In 1942, she joined a Polish underground organization, Zegota, and eventually recruited 25 members to help her rescue Jewish children.
Sendler posed as a sewer/plumbing specialist for the Ghetto. Using her truck and tool bags, she smuggled children out of the Ghetto in boxes, suitcases, sacks, and even coffins. She always brought her dog on the truck as she had trained him to bark when the Nazi soldiers let her in and out of the Ghetto so they wouldn't search her truck.
She and her helpers created over 3,000 false documents to help them escape. Co-conspirators on the outside placed the children in to safe houses, Catholic convents, orphanages, etc. then given non-Jewish aliases.
Sendler wrote down all the names of the children and hid them in a jar, buried in a garden, in the hopes of reuniting children with parents at the end of the war. Sadly, most of the parents had been killed in the holocaust.
Eventually, Sendler was captured and tortured by the Nazis. Her feet and legs were broken, still she refused to reveal her co-conspirators or hand over the names of the children. A guard finally accepted a bribe to sneak her out of the prison.
Sendler successfully smuggled out 2,500 Jewish children and 500 Jewish adults during WWII.
"Every child saved with my help is the justification of my existence on this Earth, and not a title to glory."
After the war and the Soviet takeover of Poland, Irena Sendler was persecuted by the communist Polish state authorities for her relations with the Polish government in exile and with the Home Army.