5. Irena Sendler, named Righteous in 1965

Although many Catholic Poles were indifferent or indeed openly hostile to Poland’s 3.5 million Jews—who made up 10 percent of its total population—there were some Poles who felt compelled to help their Jewish neighbors. Among them was Irena Sendler, who was a 29-year-old social worker when the Nazis invaded.

Sendler appealed to her friends and colleagues to help the Jews imprisoned behind the ghetto’s walls without food, medicine or contact with the outside world. They had to do something, Sendler believed, even if the Nazis strictly forbade interactions between Warsaw’s Jews and “Aryans.” So she used her position as a social worker in the city’s Welfare Department to obtain a municipal permit to enter the ghetto. Her pretext was to inspect sanitary conditions there.

She was preying on the Nazis’ fear that the typhus that plagued the ghetto would spread beyond its walls. But in fact Sendler used the pass as a ruse to enter the ghetto, where she hoped to provide help. Once there she made contacts with members of Jewish welfare organizations, and Sendler and her friends began to smuggle aid into the ghetto.