This is Irena Sendler, a Polish social worker and nurse who smuggled approximately 2,500 Jewish children out of Nazi-occupied Warsaw.
She entered the ghetto using a special work pass and would smuggle out children in the bottom of her toolbox and also utilize her burlap sack for larger kids. She also used ambulances and sewers to get them out of the ghetto.
She was eventually caught by the Nazis and despite being tortured and having both her arms and legs broken, she did not reveal the names nor whereabouts of the children she had rescued. She was sentenced to death but managed to escape on the day of her scheduled execution after the Polish resistance bribed Nazi officials for her release.