Last month, 67 years after the end of the Holocaust and over 20 years since his death, Yad Vashem granted this honor [of Righteous Among the Nations] to Antonin Kalina, a Czech communist who saved over 900 boys in Buchenwald.
You can read about Kalina here. His brave work in protecting these boys was not recognized for many years, because he didn't seek publicity. But there is now a film about it, 'Kinderblock 66: Return to Buchenwald'.
Explaining himself in later years, Kalina said, 'I believe in people. It was necessary to believe in oneself, and those who lost that belief were lost.' (Source.)