The death factory at Auschwitz was a closely guarded secret of the Third Reich — until two men, Rudolph Vrba and Alfred Wetzler, escaped to tell the world.

This week, as the world marks Holocaust Remembrance Day, Secrets of the Dead tells the harrowing story of Vrba and Wetzler’s escape and explores the controversial decision by the head of the Hungarian underground not to make their report public.

You can watch “Escape from Auschwitz” tonight at 8pm on PBS (check local listings) or in its entirety at Secrets of the Dead online.

Plus, follow the escape route Vrba and Wetzler cut through southern Poland after they slipped beyond the barbed walls of Auschwitz. Then learn the story of two Auschwitz survivors who fell in love after the war.