4. Jan Karski, named Righteous in 1982
Jan Karski was the nom de guerre of Jan Kozielewski, a Polish Catholic born in Lodz who acted as a courier in the Polish underground during the Nazi regime. He consistently broke into the Warsaw Ghetto to pick up and relay information, details he would then share with the west.
He is credited as one of the first individuals to give witness accounts to the White House in an aim to encourage US assistance.