When it was in its third season, FRONTLINE aired Alfred Hitchcock’s “lost Holocaust film.” The documentary, shot by British and American camera crews, followed Allied armies as they entered the Nazi death camps at the end of World War II.

In 1985, after finding five of the film’s six reels in a vault of London’s Imperial War Museum, FRONTLINE added a script and aired it. As Patrice Taddonio wrote in 2015, “FRONTLINE’s plan was to present the film unedited, as what the film’s producers had originally intended it to be: an unflinching documentation of the conditions of the death camps.”

Throughout the years, FRONTLINE continued to cover the raw emotion and horror of the Holocaust. In 1996, Marian Marzynski told the homecoming story of two elderly Polish-American Jews. In 2013, he returned to Poland to preserve the stories of Holocaust survivors — including himself. And in 2019, Arthur Cary turned to The Last Survivors.

Here are some of the key films and reporting from FRONTLINE’s body of work.