The girls wrote to her. Her reply came in Polish.
"My dear and beloved girls," it began, "very close to my heart."
In May 2001, the students from Kansas met Irena Sendler in Warsaw. Their play and their research helped carry her story around the world, and in 2009, it became a TV film on CBS.
She never saw herself as a hero. "I could have done more," she said. "This regret will follow me to my death."